Rāja-Vidyā: The King of Knowledge
A fish can never be happy if it is out of its water element, no matter what arrangements are made for it to enjoy. In the same way, the eternal soul, or jīva, can never be satisfied in this material world, no matter how hard it tries, for it is not in its real home, the Spiritual Kingdom of God. The way out of this material entanglement is through knowledge, and the topmost knowledge is the cultivation of Kṛṣṇa Consciousness. The more one immerses in the study and practice of The King of Knowledge, the more one returns to his or her eternal nature, experiences meaning and direction, and becomes happy, even in this world. In fact, happiness is a symptom of one who walks in knowledge.
This easy to read book by His Divine Grace A.C. Bhaktivedanta Swami Prabhupāda stresses and expounds upon these points, explains how real knowledge is passed down purely through a qualified lineage of teachers, and offers many practical illustrations and references that serve to bring us closer to re-uniting with the Supreme Personality of Godhead.