Day 1: First "genre novel."
I've tried to figure this out on several occasions, from tracing my history with Conan and other barbarians to considering my start as an SF reader, from remembering when I first saw Frank Frazetta's art to looking at my relationship with space opera. I'm not sure that I can really point to that one book that did it. Last year I wrote a comment over at SF Signal about the subject:
"But what drew me to the genre in the first place? I grew up in a fundamentalist Christian family (and was a childhood evangelist, but that's another story), and we were expelled from the church for my father's assorted transgressions (also another story). I entered high school completely unprepared for the real world (I had been partly homeschooled, partly religious schooled, and had attended 13 different schools in-between before 9th grade), and I retreated almost immediately into books.
After exhausting the biographies of veterinarians and pet detectives, I was unsure where to go next. My cousin gave me a copy of Lester Del Rey's Rocket Jockey, which I found to be unlike anything I had read before. The book imagined things that had not happened, maybe could not happen, but that were treated as fact. I had heard to things like this, of movies such as Star Wars (which I had been banned from seeing, along with most movies in theaters). The book looked ahead and made a world out of things that might occur. I was hooked by the idea of looking at the future that way.
Uncertain how to find more books like that, I wandered the aisles of the library until something popped out. That led me to Space Cadet, which I checked out of my high school library and carried around so often that it became a derisive nickname for me. Brooks' The Sword of Shannara, which was accessible and appealing to a youngling unexposed to such imaginings, was another gift from my cousin. From here I dove into Heinlein's juveniles, Asimov, and many of the classics, and these sustained me in my freshman year until I discovered my history teacher's shelf of wonders. "
When I compare this to other writings, I realize that my chronology is mixed up. I actually read Rocket Jockey twice, the time of religious fervor in-between having partly erased the memory. All I really remember from that first reading at the age of 5 was the rocket ship, and the meteorite punching through the ship's hull. I think that was the earliest book I read, but it's hard to say that that first reading was what put me on the path. What little chronology there is in the space opera piece is vague, especially when I remember reading a couple of Heinlein's seminal works, such as Space Cadet and The Moon is a Harsh Mistress in high school (and in fact carried the former book around so much that it became a derogatory nickname for me).
I was exposed to SF and fantasy before and after my family's religious phase, and while I romantically like to draw narrative connections between them, I did not really become a reader of fantastika until I was in high school and came under the influence of my history teacher Mr. Cahoon, he of the cabinet of book wonders. There's no doubt that Rocket Jockey was important, but so were the planetary romances of Burroughs. Heinlein gave me a lot of words to dive into, but so did Poe (and I was profoundly affected in middle school by Lorne Greene's readings of his works, especially "The Cask of Amontillado"). And yet I did feel really brought into the genre until I read Le Guin and Delany, and had my skull cracked open by their imaginations. For me, it took a number of books to make me a fan, and later writer, of genre literature.