Maybe that’s where fear comes in. As Greil Marcus put it in Lipstick Traces:
I began to poke around, and the more I found, the less I knew.
The biggest help to me with my books comes from something Stewart Brand said to Brian Eno, captured in his diary, A Year of Swollen Appendices:
“Why don’t you assume you’ve written your book already — and all you have to do now is find it?”