Why is this book so good? California Pit River Indian tales for children? Sounds like a total bore.
It is instead totally engaging, delightful and very moving.
The best (American?) writers write like this--transparently clear, relaxed, intimately. I'm thinking of Williams, Sherwood Anderson, Rexroth, Wendell Berry, Gary Snyder, etc. This style is really not a style at all, but expression of a certain kind of ease and mastery. This here is a very simple book, so any missteps, no matter how slight, would stand out. There are none.
De Angulo may have learned how to tell a story from the northern California Indian storytellers he worked with for many years; their humanity, humor and wisdom shine through the book.