This work, published in 1901, is the culmination of a lifetime of research and contemplation in which Richard Maurice Bucke (1837–1902) expounds his theory of the development and evolution of consciousness in living things. He uses his own experiences, those of contemporaries such as Tennyson, and of historical figures such as Francis Bacon, as evidence for moments of higher consciousness and intellect known as 'cosmic consciousness'. Bucke's theory is of three states of progressive consciousness, attained through evolution. The Simple Consciousness of animals, Self Consciousness of man to understand his place in the universe, and Cosmic Consciousness, where man might grow to understand the life and order of the cosmos. This pinnacle of understanding is a progression assisted by evolution that Bucke hopes will one day come to all men. A thought-provoking book at any time, full of optimism for the intellectual future of the human race.