This is a huge book of over 400 pages in which Brunnholzl in which he explores in detail writings by the famous Nagarjuna which are rarely examined. Nagarjuna is known for founding the Middle Way  (Madyamaka) school which is the foundation of second turning of the Wheel of Dharma explaining how everything is insubstantial or "empty of inherent existence." There are literally hundreds of books on Nagajuna's books on emptiness and these were adopted in Tibet and later labeled as the Rangtong (empty of self) view of Emptiness.

However, Nagarjuna also wrote a set of "collection of praises" which champion another view of emptiness which is known as the Shentong (empty of other) view. This Shentong view was accepted by the Third Karmapa and several sucessing Karmapa and became the Kagyu view of emptiness. 

In this book Brunnholzl gives a detailed summary of Nagarjuna works and then he translates  Praise of Dharmadhatu by Nagarjuna and then translates the Third Karmapa's commentary on this text.