Until a better translation comes along, this is one of the only English works on Master Chih-i who has been a reference for Zen and Esoteric Buddhists in Japan for centuries.

The concept Shikan (Jp.) Chi Kuan (Chinese) is that of Stopping & Seeing. This is the basic meditation of Buddhism, (Shamatha and Vipashyana).

The work is also one of the few Buddhist documents that references Incense used in Buddhist meditation.

A good reference in respect to the incense mentions is Bedini's "Trail of Time" and the Chapter regarding the Nalada monks going to China, and the Incense Seal of Avolokitesvara.