The Samadhi of Direct Encounter with the Buddhas of the Present
Anyone who is serious about Pure Land studies must have this title. Not only is this book one of the foundation texts used in China to begin and resurgence of Pure Land Buddhism from India, it is incredibly detailed for visual meditations to actually view the Pure Lands, Buddha's, and Bodhisattvas. Another key teaching point that expands this above the two normal Pure Land Shoter and Longer Sukhavativyuha Sutras is the basis of moral teachings to set up guidelines for sangha practice and foundations, almost like the Theravada Vinaya.
This tomb is vastly more complicated than the shorter/longer sutras but is much more detailed on personal practice and moral obligations as a follower of the Dharma where as many pure land schools pass over this very basic principle for the more simplified and less academic practice. Faith alone is a foundations but more from the basis of a school and lineage teachings, not the Buddha's. Faith needs a vehicle and this sutra grants that availability of scripture to create and full pure land practice without any holes or worse, personal interpretation of what to do in this "branch" of Buddhism.
This sutra also sets up the practice for solitary students that wish to be as intense as they could ever hope to be.