No, the sole purpose of this memoir, like many, many others concerning some personal trial, is to generate sympathy for its author. Manning, who was in his mid-20s when he took his lengthy turn at the bedside, seems on every page to be looking for someone to say, “Poor Sean; how about a hug?” But it’s the reader who will need a hug after choking down this orgy of self-congratulation and self-pity. That’s what happens when immature writers write memoirs: they don’t realize that an ordeal, served up without perspective or perceptiveness, is merely an ordeal.

3

If you’re jumping on a bandwagon, make sure you have better credentials than the people already on it. Imitation runs rampant in memoir land. There can’t be just one book by a bulimic or former war correspondent or spouse of an Alzheimer’s sufferer; there has to be a pile. And lately, the biggest pile of all has been books by parents, siblings and teachers of people with autism.

Allen Shawn, who teaches at Bennington College, is the latest to climb on this heap, with “Twin.” The gimmick: his twin sister, now in her 60s, is autistic. Seems like a potentially interesting variation of the overworked theme. Until, that is, you start reading the book and realize that Shawn’s parents — his father was William Shawn, editor of The New Yorker — had his twin, Mary, institutionalized when she was 8, and that, psychic twinship or not, Allen Shawn doesn’t really know a thing about her.

Shawn describes how the family would arrive in a limousine for their occasional visits with Mary, an image that will infuriate those who have not had the luxury of paying someone else to make their problems go away. “Only a more naturally unified and self-sacrificing family than ours could have tolerated the enormous challenge of bringing her up at home,” he writes of Mary, part of a stunningly tone-deaf attempt to explain away the institutionalization as necessary because the rest of the family was quirky and William Shawn was busy not only with work but also with being a lifelong adulterer.

Institutionalization was just what people did back then, you say? “I am awestruck that, even in the time of my childhood, there were families that had the love, fortitude and resourcefulness to incorporate such children into their world,” Shawn writes near the end of this appalling example of coattail-grabbing. Yes, there were. And they’re the ones who are qualified to add to the heap of autism memoirs.

4

If you still must write a memoir, consider making yourself the least important character in it. That is basically what Johanna Adorjan has done in “An Exclusive Love” (translated by Anthea Bell), her spare, beautiful exploration of why her grandparents killed themselves. Adorjan, a journalist in Berlin, artfully reconstructs the day in 1991 when her grandparents, who lived in Denmark, took their own lives in a suicide pact. Although she is part of the story, she wisely keeps herself on its edges, occasionally noting personality traits or mementos she inherited from her grandparents, but mostly bringing the two of them to life through her recollections and the memories of contemporaries she interviews.

“We all felt the force of her thrift,” she writes of her grandmother. “Her presents were always received apprehensively: what were we not going to be pleased to get this time? I remember T-shirts much too small for me, and you knew from the smell of them that they had been in my grandparents’ house for a long time (in fact they smelled as if they had been stored in an ashtray). A book that looked as if it had been read. A bottle not quite full of bath foam.”