It's taken six decades for this early novel by the Portuguese great to reach publication. Now it illuminates the development of a radically original artist

José Saramago submitted the manuscript of Skylight to a Lisbon publisher in 1953. Receiving no response, and apparently never seeking one, he was plunged, says his wife Pilar del Rio in her introduction, "into a painful, indelible silence that lasted decades". He did, however, make a reputation as a journalist and editor before he returned to writing fiction in 1977. In 1989, having published three novels, he was at work on a fourth when the publisher to which he had sent Skylight wrote to say that they had rediscovered the manuscript and it would be an honour to print it. Saramago went at once and brought it home. His wife tells us that he never read it and said only that "it would not be published in his lifetime". We must assume that he said nothing about what was to be done with it after his death.

An old humiliation might be at the root of his neglect of the manuscript, or perhaps, given his late second start, he didn't want to spend time on a return to this more conventional early work. In any case, I think his wife's decision to publish it now was sound. Not only does it illuminate the slow development of a radically original artist, but it is an interesting novel in its own right. The translator is the irreproachable Margaret Jull Costa.

Had the manuscript been accepted, and successful, would Saramago have kept the fine indifference to opinion that let him gradually discover his own incomparable idiom, style and subject matter? There's no telling.

Paragraphed and punctuated conventionally, Skylight follows a familiar fictional formula: a set of characters thrown together in one place at one time. In this case it's a small working-class apartment house in Lisbon around 1950, and six flats, 15 people, 10 of them women. Their lives are fragile, frugal, hard. Adriana and Isaura just manage to support their mother and aunt. In the evening, all four women listen with yearning intensity to Beethoven on the radio, while young Claudinha next door plays jazzy ragtime. Claudinha's parents are unhappy in marriage. Emilio the salesman and his Spanish wife loathe each other. Brutish Caetano and diabetic Justina, haunted by the loss of her child, go past hatred into open violence.

The explicit sexuality of the book (which may have kept it from being considered for publication in Salazar's Portugal in 1953) is remarkable now only because it is so compassionate. Saramago's sympathy with the two sisters whose sexual desire can find no outlet is deep and subtle, as is his respect for Lidia, the kept woman who, while despising her keeper, respects her own professionalism in the most despised of professions. By a stunning reversal of erotic power, Saramago even manages to redeem the tiresome, porny cliche of a woman responding to rape with passion.

Frustration, moral squalor, insecurity, all at close quarters, inevitably breed competition and malice. Moving from character to character, the loosely plotted story includes a good deal of mean-spirited evildoing, quite in the tradition of Balzac and the naturalists. It also includes dry humour, and at least one tranquil domestic scene revealed suddenly as almost visionary:

"Then they had supper. Four women sitting round the table. The steaming plates, the white tablecloth, the ceremonial of the meal. On this side – or perhaps on the other side too – of the inevitable noises lay a dense, painful silence, the inquisitorial silence of the past observing us and the ironic silence of the future that awaits us."

The strongest character in the book is Silvestre the cobbler. In later Saramago novels careful, honest workmen like him will appear, always significant, always wearing their significance lightly. Silvestre is married to Mariana, "so fat as to be comical, so kind as to make one weep" – a thoroughly good marriage of calm-souled, generous people. The reactionaries who now control his country crushed Silvestre's fierce social and political hopes, but not his spirit. He is a patient man, and his patience, his contentment, come across as far more than mere accommodation to defeat.

On the edge of poverty, Silvestre and Mariana rent their spare room to a lodger, Abel. He's about the age of the author of the book, 31 or 32, and it's hard not to read him as to some degree a portrait of the artist as a young man. Purposefully avoiding close connection or commitment to anyone or anything, Abel appears a literary type of his time: the young man who holds himself aloof, guarded, perceptive, inherently superior, essentially joyless. Though he wins his arguments with Silvestre, Abel strikes me as being not as old – nor as wise – as he thinks he is. Are his existentialist poses a bit self-indulgent? Silvestre earned his disillusionment the hard way, staking himself on committed radical action. Abel isn't going to waste his life on illusions. But where will his non-commitment take him? Is he a realist reserving himself to act when action can succeed, or an idealist denying his own paralysis?

In their last argument, Abel gets the last word, in fact the last words of the book: "The day when we can build on love has not yet arrived." In the final silence after this statement, I sense an unspoken refutation or qualification, which is the fact of Silvestre's life, a hard-working, responsible life built, in the most modest, limited, practical way, on love.

• Ursula Le Guin's The Unreal and the Real is published by Gollancz. To order Skylight for £13.59 with free UK p&p call Guardian book service on 0330 333 6846 or go to guardianbookshop.co.uk.