Instruct: Classify a given review into positive or negative sentiment.
Query: Rolf Geibel's contribution to Numata's English Tripitaka gives these esoteric Tantras to the Western world

The Susiddhikara and Tattvasamgraha Sutras respectively dominate the Kriya and Yoga section of the Mahayana Tantra. Rolf Geibel has translated the texts from the Chinese and the works being of such critical importance in the path to complete Buddhahood, one is deeply humbled by the existence of this treasure text of esoteric Mahayana Buddhism. The teachings set forth here by the Buddha, Vajrapani and so on in various emanations are highly mystical and one can only penetrate the profound truths with the vajra- or diamond-like gnosis of a bodhisattva. For those serious about achieving the ultimate understanding of all phenomena, these twin texts are stepping stones of collosal importance.