In an interview about his new novel, Dissident Gardens, Jonathan Lethem expresses his ambivalence about historical facts informing fiction:
I don’t really like research in fiction. The results are often leaden. And yet here it was necessary that I build a giant armature of factual situations in my head, a historical diorama to move through, even if I then contradicted it or blew it up at whim. I researched rhetoric and propaganda, as well as dull sociological stuff. I read mediocre novels written from the left, from the ‘30’s to the ‘60’s, to gain a better feel for the emotional texture of those stances through those decades. This wasn’t pleasure reading! I wouldn’t recommend many of the books to anyone, putting apart a handful of vivid memoirs, mostly already favorites …
Of course, in the writing, Dissident Gardens couldn’t bear much of what I’d learned. Novels don’t want to be crammed with factual stuff. I mostly left it aside, including some astonishing truths, which when you first come across them, you think, holy shit, I’ve learned this crazy thing and now I’ll blow people away by revealing this knowledge in the book! But at the juncture where you’d insert such a thing, you flinch, seeing the cost is too high. The facts will intrude — either on the reader’s experience, or my own relationship to the page, to the dream.
The Dish 