The Complete Pinball Book by Marco Rossignoli.

'The complete pinball book' is, like its title says: complete.
You need to buy this book if you are looking for one book that you will use as a reference.
Really: probably every pinball machine you will ever read or hear about is mentioned in this book. There will be something written about it or it will have pictures of that machine.

The book is much more than just a reference book. It has a wealth of information. It's not just a list of games with pictures. Each chapter of the book describes the evolution of a specific part. Flipper setup, multilevel games, pop bumpers, every aspect about pinball machines that has changed over the years is described.

The book also has lots of nice pictures, overviews and details. It really is a must have for everyone who is interested in pinball machines.

Here is the official passionforpinball.com website about this book with more information.