By Paul Stamets. The most comprehensive field guide to the psilocybin-active species ever published, this field guide illustrates a wide range of species spanning the world. With excellent color photographs, nearly 100 species are fully described, including close relatives and poisonous look-alikes. A book without comparison, this field guide stands alone in its scope and describes many new species not seen in any previous works. 6 x 9 inches, 256 pages. Softcover.