David Gerrold is a cult science-fiction author. For people who care about Star Trek he has written episodes and is the author of the book "The Trouble with Tribbles". For fans of military SF he wrote the four books in "The War Against the Chtorr" series - we have been waiting twenty years for the final volume(s).
And then there is his time-travel novel "The Man Who Folded Himself". Gerrold is a career-acolyte of Robert Heinlein: "The War Against the Chtorr" series is explicit homage to "Starship Troopers" while "The Man Who Folded Himself" parallels exactly Heinlein's classic "All You Zombies".
So what to make of it?
Gerrold starts promisingly in the style of "The Catcher in the Rye". Danny is the truculent, bored adolescent orphan being paid $1,000 a month by his 'Uncle Jim' to attend University. As he observes: "An apartment, a car and a thousand a week for keeping my nose clean."
Soon however Uncle Jim dies and Danny is left with a timebelt, a personal time machine. Now Gerrold leaves his promising story development to spend 7 technophilic pages describing this device to no advantage to the underlying narrative whatsoever. What did his editor think he was doing?
We soon revert to old-fashioned story-telling as Danny and his one-day-advanced doppelgänger go to the races and clean-up. Cue another techno-excursion into multiverse-ontology as Gerrold presents his solution to the obvious paradoxes: plot development stalls and dies at this new irruption of fan-boy geekdom. Eventually the story resumes although with less élan as Danny meets a female version of himself (Diana) from a remote alternate timeline and they produce a male boy. Well, you can see where it's all going to end up.
Somewhere between here and there Danny ends up fancying himself rotten and Gerrold devotes some pages to explore homosexual relationships. In his afterword Gerrold makes a big issue about his dilemma as to whether to include this topic and his difficulties in writing it. However this all seems to me ridiculously self-indulgent. The question is whether the gay sex episode is consistent with and necessary to character and plot development. In fact it's gratuitous and contrived.
Gerrold is basically a good writer and an intelligent man: I am still waiting impatiently for his final book in the "Chtorr" series. But he takes his own opinions and his own sexuality far too seriously and this self-centredness detracts from his literary accomplishments. So if you want to see the difference between 'mere science-fiction' and literature then here it is in the nutshell. There was a good novel trying to get out here but Gerrold strangled it by gratuitous techno-info-dumping and gay-rights-prosletysing. He may believe this is a strength of genre-writing but it isn't.