What Book Changed Your Life?

Is there a book that legitimately changed your life?

I've one, though not in the way you might think. I began my career as an English teacher (I taught Rhetoric and Composition at Penn State) and thought, for a time, that the literary life was for me. I had sporadically entertained thoughts of writing a novel over the years, but my perspective changed when I read The World According To Garp and A Prayer For Owen Meany, both by John Irving, in rapid succession. 

I still have a non-fiction book or two in me, of this I am sure. But reading those two books all but ended my desire to write fiction. I never wanted those books (particularly "Owen Meany") to end. They were funny, and sad, and wise, and devastating, and wonderful. When I closed Owen Meany for the first time (and I've read it nearly a dozen times) I knew that no matter how cleverly I could turn a phrase, I could never make anyone *feel* the same depth of emotion with my writing as Irving did for me. Harold Bloom calls this the "Anxiety of Influence," and I readily admit to being defeated by it.
Again, I'm certainly not done writing, and my book(s) will come. But those early reads of Irving were so daunting to me--they completely stripped the wires of my self-esteem as a writer--that they changed my life. They convinced me that I didn't have the talent, and maybe not even the courage, to go where Irving did. A change--not for the better, perhaps--but change, nonetheless. And I think, in the end, that I'm better suited to non-fiction, as it turns out. Irving gave me a focus, in that sense, so I can fairly state that those two books changed me, irrevocably.

A painful admission.

Change is neither positive nor negative. Change is change. What books have *actually* changed you?