Pilgrim at Tinker Creek. It's a meditation on the micro-world, brilliantly and beautifully and stunningly written. It set me off a-reading Dillard's other works. The book deeply resonated within my soul, expressing in ways I could not the sense of childlike wonder at God's creation which I have never lost.
I was reminded of her book today while reading literary genius Eugene Peterson's The Pastor. I had at times wondered if Peterson knew of Dillard, since I found his writing approaching (but not reaching) her's. Peterson writes: "I wrote an article of Annie Dillard's Pilgrim at Tinker Creek, a book that was awarded the Pulitzer Prize. I recognized it as a tour de force in spiritual theology. I made the comment in my article that there was hardly a page in the book that didn't have an allusion to the Bible, yet there was not a single quote. Her publisher sent her a copy of the journal that contained my article. She wrote to me, 'I have been treated very generously by my reviewers. But nobody has noticed (at least no one has mentioned it) that the book is saturated in scripture. I wondered if anyone ever would. Thank you for noticing.'"
I've also read...
The Writing Life (if you want to learn some things about writing, read this)
Teaching a Stone to Talk: Expeditions and Encounters (contains the brilliant fictive essay "An Expedition to the Pole")
Holy the Firm (an 80-page meditation on nature and, among other things, suffering)
In my reading career the only writer who can surpass Dillard's literary genius is Flannery O-Connor.