Graves, K. 2000. Designing Language Courses: A Guide for Teachers. Boston, MA: Heinle &Heinle.
Chapter 9, “Adapting a textbook,” goes into more detail about ways to adapt a coursebook at the syllabus, unit, or activity level with step-by-step example from teachers. It also discusses the “hidden curriculum” of coursebooks.
Rinvolucri, M. 2002. Humanising Your Coursebook: Activities to bring your classroom to life. London: First Person Publishing.
This book describes 95 activities for using a coursebook with section on warm-up activities, grammar, vocabulary, reading, writing, listening, speaking, and assessment.
Woodward, T. 2001. A Central Tool: The Coursebook, p. 145-160 in Planning Lessons and Courses. Cambridge University Press.
This section includes ideas for orienting yourself and the students to the coursebook as whole as well as thoughtful ways to adapt it.