The past six years have seen unprecedented activity in the study of the hallucinogenic mushrooms of Mexico. So diverse and extensive has this activity been, and so numerous are the publications about these mushrooms and their derivatives, that we believe a bibliography on the subject is timely. It will prove useful, we hope, in mobilizing our knowledge about them and in facilitating further research. This interest- scientific, cultural, popular- flows directly from the writings of Roger Heim and the Wassons. On February 13, 1956, Professor Heim submitted his first Note about these mushrooms to the Académie des Sciences, Paris, based on the discoveries that my wife, Dr. Valentina P. Wasson, and I had made in the Sierra Mazateca, Oaxaca, in the summer of 1953. This initial Note , published in the Compte rendu of February 20, has been followed at intervals by others. In the spring of 1957 my wife and I brought out our book, Mushrooms Russia and History , the fruit of almost thirty years of intermittent research. Timed to coincide with its appearance, we published articles of haute vulgarisation on our Mexican mushrooms in Life (illustrated with reproductions of water-colors of the mushrooms by Professor Heim) and in This Week . Meanwhile Professor Heim was enlisting teams of scientists to work on the mushrooms. He himself has naturally coped with the mycological problems, ably assisted by his technician, Roger Cailleux. The scientists of the Swiss pharmaceutical house of Sandoz A. G. were quick to help. Drs. Arthur Brack and Hans Kobel succeeded in developing mass production of the fungal material in the laboratory. Dr. Albert Hofmann (discoverer of LSD-25, a substance kindred to the active principles found in the hallucinogenic mushrooms) isolated the two active agents, psilocybin and psilocin , and with his colleagues defined their molecular structure and succeeded in synthesizing them. Dr. A. Cerletti with his colleagues studied their pharmacological and physiological properties. Professor Jean Delay, the eminent French psychiatrist, was the first to head up a team to experiment clinically with psilocybin and psilocin at the Hôpital Ste. Anne in Paris. All of this activity culminated in the appearance of a book, Les Champignons Hallucinogènes du Mexique , large in format and richly illustrated, in the writing and editing of which Professor Heim was the prime mover. I contributed the historical and anthropological chapters, and Professor Heim did me the honor of joining my name to his as co-author on the title page; the Sandoz and Delay teams also made their several contributions. My wife and collaborator died at the end of 1958, and, when the book appeared a few weeks later, it was dedicated to her memory. It is appropriate, even inevitable, that, because of their number and broad scope and the quality of Professor Heim's contributions, his publications and ours be listed together in the first section of our bibliography. The second section, divided into three parts, deals with the past: a) Primary Sources , b) Later References, and c) Archeological. Under a) Primary Sources we give the citations for all references to the sacred mushrooms known to us in the early Mexican writings. As time goes on, more will certainly be uncovered. A promising area to explore lies in the body of surviving Nahuatl literature, largely in manuscript and mostly unread; Nahuatl is the language spoken by the Aztecs and many other peoples of Middle America at the time of the Conquest. Our b) Later References includes such citations as we have found in writers who are posterior to the Primary Sources (the last of these being Bishop Lanciego in 1726) and down to and including William E. Safford in 1915. During these two centuries the record shows no first-hand contact by white men with the sacred mushrooms, no field trips, no curiosity about them. The sacred mushrooms of Mexico had never arrested the attention of the great outside world. Now they were known only to a few scholars poring over dusty tomes and records, who occasionally would mention them perfunctorily in their own obscure publications. Then finally Safford appeared on the scene and delivered, as he thought, the coup de grâce by declaring in an elaborate paper read before a distinguished society in Washington (later published with photographs and footnotes in a learned journal) that the vision-producing mushrooms had never existed. They had been, it would seem, an hallucination of the Spanish padres . The entries under c) Archeological are contributed by Dr. Stephan F. de Borhegyi, Director of the Milwaukee Public Museum, who for more than ten years has studied the "mushroom stones" of Middle America, those artifacts long considered enigmatic that we interpret as the symbol of the religious cult of our sacred mushrooms. Following each entry in this sub-section Dr. de Borhegyi has added his illuminating comment. The third section in our Bibliography is anthropological, reflecting the revivified interest in the ways of the Indians leading their own lives today in the mountains of Oaxaca, Puebla, Vera Cruz, and the vicinity of Mexico City. The fourth section is mycological. The fifth chemical, the sixth pharmacological, and the seventh psychological, psychiatric, and clinical. The entries in these sections five, six, and seven often overlap, and therefore we have made them into a single list, but we have indicated in brackets to which sections each entry belongs. The eighth section covers parapsychological items; the ninth, cases of accidental ingestion of hallucinogenic mushrooms; and finally book reviews are listed in the tenth section. Much has been published on our mushrooms and psilocybin in the lay press, in many countries. Our bibliography does not attempt to cover these articles: perhaps they will be the subject of a brief paper on a future occasion. We have tried to make our entries complete to January.