The author is Christopher Hale and the subtitle is the rather misleading Exposing Britain’s My Lai.
The first fifth of this book is in fact the best short early economic history of Malaysia and Singapore I know, even though the focus of the book as a whole is on one colonial event, namely the 1948 Batang Kali massacre during the post-war Malayan Emergency. The next section is a superb treatment of the Japanese occupation and the political issues leading up to that occupation. This book reflects a common principle, namely that often, to learn a topic, you should read a book on an adjacent but related topic, rather than pursue your preferred topic directly. The book on the adjacent topic often will take less background knowledge for granted and explain the context more clearly for what you actually wish to learn, while getting you interested in other topics along the way.
Just about every page of this book has useful and interesting information, here is one new word I learned:
The history of the ‘Malay World’ in the centuries before the momentous fall of Malacca to the Portuguese in 1511 is predominantly a convoluted narrative of maritime statelets, technically thalassocracies.
This one will make my best non-fiction of the year list.