This book is a fascinating book that focuses on the spies and their activities operated by the KMT, CCP, the Japanese, the Germans, and the Russians from 1911 to 1949.
The writer has read widely. Unfortunately, this book had not been proof-read by a good editor or even by its writer.
Some characters are introduced without context and out of context, the index is incomplete, the bibliography does not list all the sources cited in the book and the paper back font is too small.
This is a pity as otherwise this book is a very interesting book. So, persevere and you will still enjoy this book.