"The Complete Sourdough Cookbook"
by Don and Myrtle Holm.
When the words "complete" or "ultimate" appear in a book title, I get suspicious. And the suspicion is usually well founded.
There's lots of good historical information, lots of good folklore, and a fun read in this book, but it's not a terribly good sourdough cookbook.
The authors suggest the use of commercial yeast, which suggests they really don't understand, or trust, their sourdough culture.
Recommended for fun, not for sourdough baking. isbn.nu can find a number of vendor with copies.