The Passive Solar Energy Book by Ed Mazria.
An essential source on solar passive, charmingly and beautifully illustrated. One of our fav sources for inspiration and design information, I cant recommend it highly enough.
ISBN 0-87857-260-0 – hardcover
ISBN 0-87857-237-6 – softcover
This book is no longer in print (our version was published in 1979!) but you can get a copy secondhand on the ABE book exchange online.
Although framed in imperial units this book so clearly and charmingly written and illustrated that it forms the foundation of our solar passive library.