Books on Accessibility

Accessibility for Everyone, Laura Kalbag – an introductory book

Microcopy: the Complete Guide, Kinneret Yifrah – includes some valuable chapters on error messages, designing empty states, and cognitive accessibility

Form Design Patterns, Adam Silver

Apps for All, Inclusive Design Patterns, and Inclusive Components by Heydon Pickering – the most highly respected books on accessible app design

Web Accessibility for Developers, Toronto Metropolitan University – an open textbook on ARIA. Note that many examples use divs incorrectly to trigger actions; see the Button Cheat Sheet for a brief explanation of why this is wrong.