1 Leonard Cohen has been labelled "the poet laureate of pessimism", "the grocer of despair", "the godfather of gloom" and "the prince of bummers". He has, none the less, given pleasure and even laughter to the million or so people who buy his records.

2 He will be 70 on Tuesday, the first of the 1960s singer-songwriters to reach 70. He was born in 1934, shortly before Elvis Presley.

3 His new album, Dear Heather, is out next month. It includes a song about September 11, called On That Day.

4 Since his mid-50s, his stock has risen steadily. Late middle-age tends not to be easy for pop stars, if they get there at all, but it has smiled on Cohen. There have been several tribute albums and covers by Bono, REM and Johnny Cash. His influence has been cited by Nick Cave, Suzanne Vega and Rufus Wainwright, who said recently: "I really believe he's the greatest living poet on earth."

5 Cohen's albums regularly go to no 1 in Norway.

6 In America, his last album entered the Billboard chart at number 143.

7 In 2001 he said: "When Alberta Hunter was singing many years ago, at 82, I came to New York just to listen to her. When she said 'God bless you', you really felt that you had been blessed. It's wonderful to hear a 20-year-old speaking about love. As the Talmud says, there's good wine in every generation. But I love to hear an old singer lay it out. And I'd like to be one of them."

8 Birthday parties are planned in Toronto, Edmonton, Barcelona and Toowoomba, Queensland. In Barcelona, a singer will perform Cohen's songs in Catalan.

9 Cohen was 32 and an established poet and novelist before deciding that songwriting might pay better. When he first touted his songs around New York, agents said to him: "Aren't you a little old for this game?"

10 He has never married - "too frightened". He had two children with Suzanne Elrod, and also had a long relationship with the film star Rebecca De Mornay.

11 "The heart," he says, "goes on cooking, sizzling like shish kebab." He likes the image so much, he used it to interviewers in 1977, 1988, 1997 and 2001.

12 He has used many musical styles, from acoustic folk to electro-pop. But his lyrics have made only one stylistic leap, from lush lyricism to dry humour. His vocals have gone from a limited but appealing wail to a heroically smoky rumble. Soon, he may be audible only to dogs.

13 Cohen's maternal grandfather, a rabbi, wrote a 700-page thesaurus of Talmudic interpretations.

14 His father, who was in the garment trade, died when he was nine.

15 His middle name is Norman.

16 His first band, formed when he was 17, was called the Buckskin Boys.

17 In his high-school yearbook, he gave his ambition as "world-famous orator".

18 At McGill University, he was president of the debating society.

19 His friends were fellow poets. "Each time we met, we felt that it was a landmark in the history of thinking, let alone poetry."

20 Cohen was a poet and novelist before he was a pop star. He published his first volume of poetry at 22, and won a $2,000 scholarship to travel around Europe when he was 25.

21 He liked the Greek island of Hydra so much that he bought a house there in 1960 for $1,500. It had no electricity or running water. He could live there for $1,000 a year, so he would go back to Canada, earn the money with his writing and head back to Hydra "to write and swim and sail".

22 His second novel, Beautiful Losers, about a love triangle, was hailed by one reviewer as "the most revolting book ever written in Canada".

23 His big break was meeting the folk singer Judy Collins. He sang Suzanne down the phone to her and she immediately promised to record it.

24 He was then asked to lunch by John Hammond of Columbia Records, one of rock's greatest talent-spotters: he had signed Bob Dylan, and went on to discover Bruce Springsteen. Hammond asked Cohen to sing some songs in his room at the Chelsea hotel. He played six or seven, and Hammond said: "You got it". Cohen never worked out whether he meant he had a contract or merely a gift.

25 A week later, they were in the studio, with Hammond as producer. Cohen started singing and Hammond said on the intercom: "Watch out Dylan!"

26 The young Cohen's signature tune was Suzanne. He once called it "journalism", as the details were drawn from life in Montreal. Suzanne was a friend, Suzanne Verdal, who really did serve him tea and oranges in her loft by the river. Cohen wrote the line "I touched your perfect body with my mind" because she was married to a friend of his.

27 Singing it in concert decades later, he sometimes found the emotions hard to unearth. "I was never so good that I could make a song sound real or authentic without it being that, and if it isn't, people know. I find that quite a lot of red wine will do it."

28 He is a lifelong manic depressive. Asked about drugs, he has said: "The recreational, the obsessional and the pharmaceutical - I've tried them all. I would be enthusiastically promoting any one of them if they worked."

29 From 1965 to 1968 he was a vegetarian. A few years later, he took up yoga.

30 Some time in the early 70s, his songs were dismissed as "music to slit your wrists to". The phrase stuck. "I get put into the computer tagged with melancholy and despair," Cohen said. "And every time a journalist taps in my name, that description comes up on the screen."

31 His hero is Federico García Lorca. Cohen named his daughter after him: "She's a lovely creature, and very inventive. She really deserves the name." He translated a poem of Lorca's into the song Take This Waltz, which took him 150 hours.

32 On Anthem (1992), he wrote: "There is a crack, a crack in everything, that's how the light gets in." Later he said: "That's the closest thing I could describe to a credo. That idea is one of the fundamental positions behind a lot of the songs."

33 His song Chelsea Hotel No 2, about Janis Joplin, may be the only song overtly written by one pop star about sex with another. "You said to me then, you preferred handsome men, but for me you would make an exception ... giving me head on the unmade bed, while the limousines wait in the street."

34 Much later, he said: "I never discuss my mistresses or my tailors." But for Joplin he had made an exception.

35 One woman who resisted his charms was Nico, whom he met at Andy Warhol's club in 1966. "The most beautiful woman I'd ever seen." She said she preferred younger men, but introduced him to Lou Reed, who had some of his books. "We told each other how good we were."

36 In 1968 he moved with Suzanne and the children to a cabin near Nashville. John Hammond said, "Nashville was astounded by him, because they hadn't seen anything like him, and they never will again."

37 Cohen has been with Columbia for 37 years, but relations are ambivalent. Accepting an award in 1988, he thanked Columbia and said: "I have always been touched by the modesty of their interest in my work."

38 When he wrote Bird on a Wire, Cohen felt he hadn't "finished the carpentry", but Kris Kristofferson said the first three lines would be his epitaph: "Like a bird on a wire/ Like a drunk in a midnight choir/ I have tried, in my way, to be free"

39 When sport loomed ever larger in the 90s, some in the music business were taken by surprise, but not Cohen. "In the 60s, music was the mode, the most important form of communication," he said in 1988. "I think today it's sports. The sports figures in America are much more attractive and interesting and their lives are much more dangerous than the rock figures. They are in the traditional heroic mode."

40 Asking him where the songs come from is fruitless. "If I knew, I'd go there more often."

41 His album Death of a Ladies' Man was produced by Phil Spector, the reclusive genius of girl-group pop. "I was flipped out at the time," Cohen said later, "and he certainly was flipped out. For me, the expression was withdrawal and melancholy, and for him, megalomania and insanity and a devotion to armaments that was really intolerable. In the state that he found himself, which was post-Wagnerian, I would say Hitlerian, the atmosphere was one of guns - the music was a subsidiary enterprise ... At a certain point Phil approached me with a bottle of kosher red wine in one hand and a .45 in the other, put his arm around my shoulder and shoved the revolver into my neck and said, 'Leonard, I love you.' I said, 'I hope you do, Phil.'"

42 Cohen has described the album they made together as "grotesque".

43 In 1988 he released I'm Your Man, and reinvented himself as a boulevardier with synthesisers and jokes. "Everybody knows you've been discreet," he sang, "But there were so many people you just had to meet/ Without your clothes."

44 Cohen's work has been chosen on Desert Island Discs by the artist Jack Vettriano (I'm Your Man), Pink Floyd guitarist David Gilmour (Anthem) and the singer and Velvet Underground viola player John Cale (Alexandra Leaving). The actress Gillian Anderson chose covers of two Cohen songs - Jeff Buckley's Hallelujah and Roberta Flack's Hey, That's No Way to Say Goodbye.

45 In 1988, Cohen told Musician magazine: "As you get older, you get less willing to buy the latest version of reality."

46 A writer in the 1950s, a folk singer in the 60s, a has-been in the 70s, a cult rock star in the 80s, Cohen decided to become a monk in the 90s. He joined a Buddhist community on Mt Baldy, near Los Angeles: in the city of permanent summer, he had gravitated to the one part of town that had winters. He acted as driver to the senior monk or Roshi (teacher), a man in his 90s. Cohen was called Jikan, "the silent one".

47 "Cohen in Roshi's company was like a fish in water, or a non-fish in non-water, or like neither," wrote Leon Wieseltier, somewhat enigmatically. Cohen was clearer: "I'm not looking for a new religion. I'm quite happy with the old one, with Judaism."

48 In 1986, he made a guest appearance in Miami Vice as a character named François Zolan, head of Interpol.

49 In 1992 he released a song called Democracy, which was unlike anything else in his oeuvre or the pop canon - a satirical march, highly politicised although not party-political. It was later used by Ralph Nader in his presidential campaign, and sung by Don Henley at the MTV Ball during Bill Clinton's inauguration ("slaughtered," according to Leon Wieseltier). The song came out after the LA riots of April 1992, but was recorded before them. "Some people have suggested that it's prophetic. It's hard to wear that mantle. But when you're writing, your antennae go up, and you're sensitive to nuances in the air."

50 Katie Melua, Britain's best-selling new singer of 2004, was asked recently what her ideal band would be. She picked John Frusciante of the Red Hot Chili Peppers on guitar, Eva Cassidy as the singer and Leonard Cohen as the songwriter.

51 In 1995, Cohen was profiled in Interview magazine by Anjelica Huston, who described him as "part wolf and part angel".

52 Cohen is always rewriting. In 1988 he was full of enthusiasm for a song he was writing called My Secret Life, but it took him another 13 years to get it right. "I can't discard a verse until I've written it as carefully as the one I would keep."

53 For many rock stars, age is something you handle with make-up, surgery or denial, but Cohen has faced up to getting old. "Now my friends have gone and my hair is grey," he sang on Tower of Song in 1988, "I ache in the places where I used to play." Seven years later, I asked him what had happened to those places. He replied with morose delight: "I can't even locate them."

54 Last year, Cohen was made a Companion to the Order of Canada by the governor-general, Adrienne Clarkson. A statement from her office described him as "a venerated dean of the pop-culture movement".

55 There was a show at Edinburgh last month about Kurt Cobain, called Leonard Cohen Afterworld. The title came from the Nirvana song Pennyroyal Tea: "Give me Leonard Cohen afterworld/ So I can sigh eternally."

56 Cohen said of Cobain after his death: "I'm sorry I couldn't have spoken to the young man. I see a lot of people at the Zen Centre, who have gone through drugs and found a way out that is not just Sunday school. There are always alternatives, and I might have been able to lay something on him."

57 Cohen's fans form a loose-knit cult. A convention was held in New York in June, while the Brighton festival presented an evening of Cohen's songs performed by Nick Cave, Rufus Wainwright and others under the direction of Hal Willner.

58 Online, the faithful congregate at LeonardCohenFiles.com. The webmaster is a Finn named Jarkko, who keeps a list of covers of Cohen's songs. So far, he has found 890, including 78 versions of Bird on a Wire, 44 of Hallelujah and 124 of Suzanne.

59 Hallelujah was covered by Kathryn Williams, the young British folk singer, on her album, Relations. At a recent concert she introduced it by saying, "I'd really, really, really like to shag Leonard Cohen, but I know his heart just couldn't take it."

60 In 1995 Cohen's manager, Kelley Lynch, put together Tower of Song, a set of his compositions sung by bigger stars including Sting and Bono. She asked Phil Collins, who turned her down. Cohen himself sent Collins a fax, saying: "Would Beethoven refuse the invitation of Mozart?" Collins faxed back: "No, unless Beethoven was on a world tour at the time." Cohen understood: "It's kind of a pain in the ass, to think about somebody else's dismal songs when you're not even in the studio."

61 As a marketing ploy, cafes in the US that had "the Leonard Cohen vibe" were sent a free copy of the Tower of Song album. "I'd like to go to some of those," Cohen said. "I can rarely locate my own vibe."

62 His best-selling songs on Napster are Suzanne and Hallelujah.

63 Cohen has probably the best manners in pop. When you ask how he is, he says, "Can't complain", as if he hadn't built a career on elegant lamentation. When he rings off, he says "So long", as he did, famously, to a lover named Marianne.

64 His songs have featured in dozens of films from McCabe and Mrs Miller to Natural Born Killers, and television dramas including The West Wing and The L Word. They provide an index of his rising stock: the log at LeonardCohenFiles.com lists 13 productions from the 70s and 80s, and 63 since 1990.

65 There's an episode of Absolutely Fabulous in which Jennifer Saunders and Joanna Lumley go to an awards ceremony and Saunders has to make a speech. She is so drunk that she slurringly recites the words of Bird on a Wire. The audience doesn't appear to notice.

66 Cohen was much admired in 1960s France. The president, Georges Pompidou, was reputed to take his LPs on holiday, and it was said that if a Frenchwoman owned one record, it was likely to be by Cohen.

67 Cohen's latest published work is a self-portrait for the Canadian current-affairs magazine the Walrus.

68 He always has excellent backing vocals. "My voice sounds so much better when a woman is singing with me," he has said. "Some dismal quality is neutralised."

69 His son Adam is a singer-songwriter who has just released his second album, Melancolista, written in French. His daughter Lorca is a chef turned antiques dealer.

70 In 1994, Cohen said: "If you're going to think of yourself in this game, or in this tradition, and you start getting a swelled head about it, then you've really got to think about who you're talking about. You're not just talking about Randy Newman, who's fine, or Bob Dylan, who's sublime, you're talking about King David, Homer, Dante, Milton, Wordsworth, you're talking about the embodiment of our highest possibility. So I don't think it's particularly modest or virtuous to think of oneself as a minor poet. I really do feel the enormous luck I've had in being able to make a living, and to never have had to have written one word that I didn't want to write.

"But I don't fool myself, I know the game I'm in. When I wrote about Hank Williams 'A hundred floors above me in the tower of song', it's not some kind of inverse modesty. I know where Hank Williams stands in the history of popular song. Your Cheatin' Heart, songs like that, are sublime, in his own tradition, and I feel myself a very minor writer. I've taken a certain territory, and I've tried to maintain it and administrate it with the very best of my capacities. And I will continue to administrate this tiny territory until I'm too weak to do it. But I understand where this territory is."

· With acknowledgements to LeonardCohenFiles.com and Various Positions: A Life of Leonard Cohen by Ira B Nadel (Bloomsbury, 1996). Leonard Cohen's album Dear Heather is out next month