Ray Bradbury was a highly prolific writer best known for The Martian Chronicles and Fahrenheit 451.
In Zen in the Art of Writing is a collection of essays Bradbury wrote over the years in which he chronicles many of his writing experiences, his triumphs and failures, and the wisdom he gathered along the way.
The final essay, which is also the books title, is the most enlightening. Bradbury gets more succinct and to the heart of the matter. A writers tasks are "work, relaxation, don't think". These three can be used in any order but all three are essential.