The story of the Buddha's authorizing the Sangha to accept new members establishes the legitimacy of each new bhikkhu accepted in line with the prescribed pattern. The Sangha that has accepted him owes its status to an allowance coming from the Buddha, and his preceptor belongs to a lineage stretching back to the Buddha himself. In this way, the opening narratives establish the legitimacy of the Bhikkhu Sangha and of the training for the bhikkhus as embodied in the Khandhakas and the Vinaya as a whole. As for the closing narratives, both the Mahavagga and Cullavagga end with accounts that juxtapose misbehaving city bhikkhus with well behaved wilderness bhikkhus. The placement of these accounts seems intended to make a point: that the survival of the Dhamma. The aim of this book is to present a core of this subject knowledge that is desirable for students. Every attempt has been made to keep abreast of the advances in the subject and at the same time to include the fundamentals.