Control the mind is certainly the crux of all yoga systems, including the system of bhakti-yoga or K???a consciousness which is the only practical yoga system in the present age. Indeed the Bhagavad-g?t? states that one who has controlled the mind has already reached the Supersoul, and that the controlled and uncontrolled mind are, respectively, the best friend and the worst enemy of the conditioned soul. Vai??ava Ke? is a Bengali poem written by His Divine Grace ?r? ?r?mad Bhaktisiddh?nta Sarasvat? ?h?kura. This poem contains revelations and practical guidance to aid the aspiring devotee in dealing with the types of nonsense deviations which may continue to be proposed by the mind to distract a devotee until he reaches the level of pure devotional service. The devotees and friends of ISKCON became aware of the value of these practical instructions in Vai??ava Ke? (What Kind of Devotee Are You?) when translations and commentaries on ten of its verses by His Holiness Jayapat?k? Swami were published in serial form in the (now defunct) periodical, ISKCON World Review. From that time, many devotees, including the publishers of this present volume, have desired that Vai??ava Ke?, together with its translation and commentary, be published in the form of a complete book so that its lessons could be repeatedly studied and reflected upon. One GBC member recently remarked that its publication was �long overdue.�  Therefore, it is the humble desire of the publisher to present this book for the pleasure of our predecessor ?c?ryas. It is especially dedicated to our spiritual master, His Divine Grace A. C. Bhaktivedanta Swami Prabhup?da, the Founder-?c?rya of the International Society for Krishna Consciousness who frequently quoted from the verses of Vai??ava Ke? in his lectures and books, and to His Divine Grace ?r?la Bhaktisiddh?nta Sarasvat? ?h?kura Prabhup?da, the author, as well as the Vai??avas all over the world. This book is most pertinent and relevant for those who are trying to advance in K???a consciousness at the present moment. We must frankly admit that our own �wicked minds� may have from time to time proposed just the kind of deviations mentioned in Vai??ava Ke? Many devotees have left full-time preaching and service in the K???a consciousness movement for precisely the types of reasons and rationalizations offered by the mind which are described in this book. ?r?la Bhaktisiddh?nta Sarasvat? ?h?kur has very kindly and plainly described all these subtle matters in great detail. He has also given pragmatic advice as to how the aspiring devotee may remain absorbed in the sa?k?rtana movement of ?r? Caitanya Mah?prabhu without becoming yet another casualty to the attacks of the �wicked mind� which many mistake to be their actual self as opposed to what is instead their real nature; the eternal spirit soul.