There are a few foundational texts in each sport, like Freedom of the Hills for mountaineers, and mountain bikers have long looked to Zinn and the Art of Mountain Bike Maintenance for the first and last word on their rides. We finally got around to updating to the 2018 sixth edition, and it's better than ever.
Repair and maintenance for every component on a modern mountain bike is fully covered, with great illustrations that reminded us of classics by Andy Tyson and Mike Clelland. Our newest bike has introduced us to a 1x drivetrain, hydraulic disc brakes and tubeless tires and Zinn covers all of that and a lot more, even electronic shifting systems.
Explanations are detailed, clear and engaging, and the illustrations are just fantastic and often include every variation of a particular component as well as exploded diagrams of the leading models from major manufacturers.
Zinn starts with three helpful chapters that cover tools (basic, intermediate, advanced and shop setups), repair kits for different scenarios, pre-ride and intermittent inspections, cleaning and common emergency repairs. Those three chapters alone are worth the price of admission, and then he gets to all the components including major tasks like building wheels and rebuilding shocks. There's even a chapter on fitting a bike to your body at the end, which we'd like to see at the very beginning. There's very little to nitpick here: maybe a detailed table of contents and ditch the white text on orange background for the sidebars, but the bottom line is ZATAOMBM is required reading, so just buy it.