Robert K. Yin

Oddly, the supposedly more theoretical companion to this book gives far better examples of good and compelling case study research than those found here. Yin aims for breadth over depth, his examples are underexposed and insipid, and his own misgivings about the epistemological value of case studies downplay the significance of the method.

Deservedly, the standard reference for case study research methodology. I find myself going back to it often, either for a full re-read or just for a refresher.