When I think of amnesia fiction, I think of movies like Eternal Sunshine of the Spotless Mind and Memento, and books by W. G. Sebald and Laird Hunt. The amnesia themes range from those that feature total forgetting to those that feature some kind of partial forgetting or just general forgetful untrustworthiness on the part of the narrator --- where the reader may, for example, actually recognize things that the narrator has forgotten.Gun, with Occasional Music is a ridiculous book. Who can read about a fistfight between a kangaroo and a private investigator and not be a little perplexed? Not to mention the bar full of overgrown babies with big heads, in more ways than one.
The characters in the book take drugs. They take drugs largely in order to forget things. So, like in Eternal Sunshine, erasing memories is a service of which people happily avail themselves. A more apt comparison is to the characters in Philip K. Dick's The Three Stigmata of Palmer Eldritch, who take take drugs in order to enhance their ability to play with dolls, and to escape the inhospitableness of their space colony environment.
Fans of The Big Lebowski, Who Framed Roger Rabbit?, Dirk Gently's Holistic Detective Agency and all of the many other plays on detective fiction --- I'd even throw in The Impossibly --- should check this one out as well. They way the plot is driven is closest to Lebowski. The detective kind of stumbles around through the various mysteries he takes on, and the book culminates in a nice, "She kidnapped herself, Dude!" kind of moment.
Lethem's quirky one-liners and outrageous metaphor (ala Tom Robbins) provide an independent source of entertainment.
He reached into his jacket and a little black gun appeared in his paw. He held it casually, the way you hold a candy bar or a cake of soap. Only this gun wasn't going to make anyone clean.
So bad it's good, you know? How about this one, regarding withdrawal from the aforementioned drugs.
I could feel my bloodstream panhandling my fat reserves for whatever last traces of the vital addictol they had stored away, and I could feel my fat cells turning out their pockets and saying sorry pal, there's nothing left.
One more, for the road.
What's more, there was rain in my collar and I needed a sandwich. The clouds were still bunched up in the sky like a gang on a street corner, and it looked to me like they had the sun pretty effectively intimidated.
In keeping with a primary theme, I've already forgotten the plot. It's complicated, with "a lot of ins, a lot of outs". You don't really have to keep track to enjoy the book. It's the descriptive riffs and the dialog that make this a worthwhile read.