The Abhisamayalamkara summarizes all the topics in the vast body of the prajnaparamita sutras. Resembling a zip-file, it only comes to life through its Indian and Tibetan commentaries. Together, these texts not only discuss the "hidden meaning" of the prajnaparamita sutrasthe paths and bhumis of sravakas, pratyekabuddhas, and bodhisattvas, but also serve as contemplative manuals for the explicit topic of these sutrasemptinessand how it is to be understood on the progressive levels of realization of bodhisattvas. Thus, these texts describe what happens in the mind of a bodhisattva who meditates on emptiness, making it a living experience from the beginner's stage up through buddhahood.

Groundless Paths contains the first in-depth study of the Abhisamayalamkara (the text studied most extensively in higher Tibetan Buddhist education) and its commentaries from the perspective of the Nyingma School of Tibetan Buddhism. This study consists mainly of translations of Maitreya's famous text and two commentaries on it by Patrul Rinpoche. These are supplemented by three short texts on the paths and bhumis by the same author as well as extensive excerpts from commentaries by six other Nyingma masters, including Mipham Rinpoche. Thus, this book helps close a long-standing gap in the modern scholarship on the prajnaparamita sutras and the literature on paths and bhumis in mahayana Buddhism.

Karl Brunnholzl was trained as a physician and presently works as a Tibetan translator and Buddhist teacher. He studied Tibetology, Buddhology, and Sanskrit at Hamburg University and Tibetan language and Buddhist philosophy and practice at the Marpa Institute for Translators in Kathmandu. Currently he works as a translator and interpreter for the Tsadra Foundation, Nalandabodhi, and the Nitartha Institute. In 2009 he was appointed as the first Western khenpo (abbot, in the Kagyu and Nyingma lineages) by Dzogchen Ponlop Rinpoche. He is the author and translator of The Center of the Sunlit Sky (2004), the first in-depth study of the Kagyu interpretation of Madhyamaka in a Western language; Straight from the Heart (2007), an anthology of Buddhist pith instructions; Nagarjuna's In Praise of Dharmadhatu (2007) with commentary by the Third Karmapa; Luminous Heart (2009), the Third Karmapa on buddha nature, consciousness, and wisdom; and Gone Beyond, vols. 1 and 2 (2010-2011).