Just finished reading Ray Bradbury's Zen in the Art of Writing, which contains the 1973 essay of the same name--an essay written at least one year before Robert Pirsig's application of the Koans to motorcycle maintenance.
I thought it holds up very well, especially Bradbury's main points: Don't write for money, don't write for critics, don't write for friends--write for yourself. Don't try to be highbrow, don't try to be crassly commercial--take the middle path. And do channel your emotions and personality and memories and imagination and obsessions and compulsions onto the page. When writing a story, let your characters drive the plot, not vice-versa. And listen to them, rather than tell them what to do. That's the Zen aspect, the conscious letting go that makes writing flow.
Finally, a word about discipline. Read a poem every day. And write every day. Bradbury wrote 1,000 words a day since he was in his twenties. He's now in his 90s. That's millions of words, hundreds of stories, and dozens of books.
Plus, he wrote the script for Melville's Moby Dick, directed by John Huston, in Ireland...so in a way, that makes Bradbury yet another Irish bard.
As Bradbury explains his technique: ""Every morning I jump out of bed and step on a land mine. The land mine is me. After the explosion, I spend the rest of the day putting the pieces back together. Now, it's your turn. Jump!""
Inspirational, simple, and fine. You can buy the book from Amazon, here: