The most baffling and misunderstood of Yeats's works, A Vision (1925), which is greatly different from the 1937 version, has been long out of print and is almost inaccessible. The editors have shown in introduction and notes how directly dependent Yeats was upon the experiments of his wife with automatic writing and dream visions (covering a period of six years and preserved in thirty-nine notebooks containing some 4000 manuscript pages). As Yeats wrote in the first draft of the Dedication, 'I declare that I have nto invented one detail of this system'. 'This task has been laid upon me by those who cannot speak being dead and who if I fail may never find another interpreter'. Although Yeats liked to quote Plato's admonition that none should enter the doors of the Academy who were 'ignorant of geometry'. The symbolic forms of psychic geometry outlined in A Vision were not in fact based on Plato, Swedenborg, or others of the classical writers Yeats often cited but rather on the experiments and thinking of his many friends and fellow students in the Order of the Golden Dawn and in the Society for Psychical Research. BY inquiring into the conception of A Vision and the circumstances and people surrounding Yeats while it was beign written, and by annotating the hundreds of unidentified allusions and references to art, philosophy, and literature, the editors have illuminated one of the strangest spiritual autobiographies of our time.