Selected Works (in chronological order)
The Buddhist Religion: A Historical Introduction (1997) – Richard Robinson, Willard L. Johnson, and Ajahn Geoff Ṭhānissaro
I cannot recommend this classic textbook on the history of Buddhism highly enough. Short and readable, yet thorough and precise, this must-read covers the entire history of Buddhism in a couple hundred, lively pages.
Featured in the course, " Buddhism as a Religion"