I have read and loved so many books that to limit myself to five is hopelessly reductive. But since people seem inexplicably enchanted by lists, I will play along.
Lolita, Vladimir NabokovNabokov uses language in a way that no one else can. He makes English dance. Subsequently I've read books of his that I preferred-Pale Fire, Laughter in the Dark-but Lolita marked my first exposure to him, and it changed my life completely.
Everything ever written by Evelyn Waugh
Like Nabokov, Waugh was incapable of writing a bad sentence. I don't often read a book and wish that I had written it; I have had that reaction to every one of his. Especially noteworthy are Put Out More Flags, Scoop, and the Sword of Honor trilogy.
High Mysterious Union by Ruth Rendell(a novella, found in the short story collection Piranha to Scurfy)People who draw a hard line between so-called literary fiction and so-called genre fiction are, in my opinion, foolish. Rendell is as good as any writer alive today, and this novella is my favorite work of hers.
The complete works of John Fowles
He seems curiously underappreciated here in the United States. His death in 2005 was a terrible loss for literature.
True and False, by David Mamet
Mamet deeply influenced my playwriting; everything I wrote between the ages of 18 and 23 sounded like him. Since then I've tried to find my own way, but his mark on me remains indelible. I've chosen True and False because his essays on drama were just as important to me as the plays themselves. My favorite play of his remains American Buffalo, which is in my opinion the most perfectly constructed classical tragedy of the 20th century.