Philip Pullman's Daemon Voices
There are a few books on writing that stand out as truly life-changing. For instance, Stephen King's On Writing, Jane Yolen's Touch Magic, Ann Lamott's Bird By Bird, and now Philip Pullman's Daemon Voices: Essays on Storytelling from David Fickling Books.
I've been reading it on my phone via Kindle, which may have been a mistake as I've highlighted so much text throughout, this really needs to be a book I physically own, can put tabs all over, and refer to again and again. Philip shares wonderful insights on his process, other writers' processes, the books and stories that influenced him and why, and his philosophy about writing and fantasy. This review from The A.V. Club calls it a 'Master Class on Writing.' The book is a long, thorough, entertaining, and thought-provoking read, as well as a tribute to Pullman's love of story. If you're launching into writing yourself (no matter the genre), I think you'll find much to value in this book and I highly recommend it!