Usually cited as C. D. Broad, was an English epistemologist, historian of philosophy, philosopher of science, moral philosopher, and writer on the philosophical aspects of psychical research.
The brief overviews of the moral philosophies of Spinoza, Butler, Hume, and Kant are excellent. The summary of Kant in particular (P. 116-121) is very concise, and one of the best I've seen. The fifth overview of Sidgwick and the conclusion aren't very interesting; they mostly cover the same topics as a modern meta-ethics book, with less depth and outdated terminology.