This volume, the result of an international collaboration of forty scholars, provides a comprehensive resource on Esoteric Buddhism and the Tantras in their Chinese, Korean, and Japanese contexts from the first few centuries of the common era to the present.
This is a massive tome on the transmission and practice of esoteric buddhism to China, Korea and Japan. It's rather academic in tone but fairly readable at the same time. Highly recommended if you have an interest in the topic.