Letters of Note has a 1952 letter from EB White to his editor, Ursula Nordstrom, occasioned by the impending Harper & Row publication of Charlotte's Web. Asked to explain why he wrote the book, he describes, beautifully, the circumstances of how he came to write it. But when he gets to the end, he says, "I haven't told why I wrote the book, but I haven't told you why I sneeze, either. A book is a sneeze." That guy -- he should think of taking up writing.
As for Charlotte herself, I had never paid much attention to spiders until a few years ago. Once you begin watching spiders, you haven't time for much else---the word is really loaded with them. I do not find them repulsive or revolting, any more than I find anything in nature repulsive or revolting, and I think it is too bad that children are often corrupted by their elders in this hate campaign. Spiders are skilful, amusing and useful. and only in rare instances has anybody ever come to grief because of a spider.
One cold October evening I was lucky enough to see Aranea Cavatica spin her egg sac and deposit her eggs. (I did not know her name at the time, but I admired her, and later Mr. Willis J. Gertsch of the American Museum of Natural History told me her name.) When I saw that she was fixing to become a mother, I got a stepladder and an extension light and had an excellent view of the whole business. A few days later, when it was time to return to New York, not wishing to part with my spider, I took a razor blade, cut the sac adrift from the underside of the shed roof, put spider and sac in a candy box, and carried them to town. I tossed the box on my dresser. Some weeks later I was surprised and pleased to find that Charlotte's daughters were emerging from the air holes in the cover of the box. They strung tiny lines from my comb to my brush, from my brush to my mirror, and from my mirror to my nail scissors. They were very busy and almost invisible, they were so small. We all lived together happily for a couple of weeks, and then somebody whose duty it was to dust my dresser balked, and I broke up the show.
At the present time, three of Charlotte's granddaughters are trapping at the foot of the stairs in my barn cellar, where the morning light, coming through the east window, illuminates their embroidery and makes it seem even more wonderful than it is.