The book "Giving a Damn about Accessibility" by Sheri Byrne-Haber packs alot of ideas and concepts in 49-pages. The author Sheri gives a mix of principles, approaches, and thoughts on accessibility.
She is both a mentor and also a coach for accessibility. The core theme is accessibility is that is not about technology, but people and their attitude about accessibility. The wisdom, thoughts, concepts, and ideas are a mix of motivation, pragmatism, and just good old-fashioned insight.
The only thing is that I'd love to see some accessible examples, but perhaps that's a future book Sheri?
Yet the book is a great guide for putting your foot in the realm of accessibility, and Sheri is your guide and coach in the pages as you read and learn from her insights and perspective. Just be warned, there is alot of information packed in this book, so its read, and re-read again.