Published in 1942, Producer Gas for Motor Vehicles is a fine book on automotive wood gas. It is probably too complete a book, covering commercial gas producing equipment at a time when petrol supply to the general public was rationed.
However, the book includes photographs and line drawings for all the producer gas plants of the day. If you want ideas on building your own producer plant and how to integrate it then this is the book to have.
If you wish to buy this book then I recommend you contact Lindsay Books in the US or Camden Books in the UK, where I bought my copy. Neither company lists the book now but they might have a copy lying around somewhere.