The first, which is perhaps the bible of cyanotypes today, is Cyanotype: The history, science and art of photographic printing in Prussian Blue. Describing its history, practice and variations Mike presents his New Cyanotype Process which is a modern revision of one of the oldest methods of reproducing a photographic image to paper.
The second and third books form a pair, and are still in print, covering the use of gold in photography, and the chrysotype or gold print. Gold in Photography: The History and Art of Chrysotype is the first published history of gold in the arts and photography. It is a very good read on the use of gold in art, its manifestations and it many uses in photography and a history of the attempts at creating a practical method of printing in gold going back to Herschel. Mike perfected a practical method of gold printing he calls the chrysotype, a process by which a wide range of tones can be achieved. Ironically, the only tone that can not be achieved in the chrysotype is that of gold itself. Mike delves into areas of chemistry and materials, including nanoparticle theory unknown to Herschel, to finally explain the appearance of gold prints and to solve the puzzle of creating a practical method. This ability to convert pure science into practical methods of photography is one of Mike's strengths. The second book in the pair is The Chrysotype Manual: The Science and Practice of Photographic Printing in Gold which presents instruction for the advanced alternative process photographer on how to create chrysotypes using Mike's new method.
Mike Ware's web site is a trove of information on the iron-based alternative photographic, or siderotype, processes. There is a detailed article on the re-invention of the chrysotype process.
Alternative photography process books are typically done in small printings, destined most often to never see a second edition. The Cyanotype book is only available used and fetches a premium. The chrysotype books are still available on Siderotype.com and can be paid for by Paypal.
I am not one to give out advice in strict ways, but these books on chrysotypes are a gold mine of information on the iron-based processes in general, and will occupy a place of honor in your collection. Don't complain to me when they go out of print. You have been warned.
Mike Ware's photography can be found in his online galleries.