The 19 essays gathered herein were produced as newsletters while Weil was a Fellow of the Institute of Current World Affairs. The fellowship allowed the Harvard-trained physician to travel in the USA, Central & S. America, following his heart's desire: the pursuit of altered states of consciousness as a means of realizing the full potential of the human nervous system. The "marriage of the sun & moon" is, just one of many metaphors he chooses (based on his experiences of eclipse-watching) to express the transcendent feelings experienced when there's union between complementary states of mind (conscious/unconscious; higher/lower). He emerges as a very open person, just the sort to try for a high--& be successful. Indeed, he makes a point of saying that altered states of consciousness are inherent in the nervous system & can be triggered by many sorts of events--dancing, drugs, the sweatbox, eclipse-watching, even vomiting--which cultists can learn to control. He also stresses that a lot depends on set & setting. One man's hallucinogen is another man's poison. Most of the essays deal with drugs. Here, he emphasizes what he considers to be significant differences between the use of the natural plant (good) vs. the synthesized or purified extract (bad). Thus, in an essay on cocaine he contrasts the merits of chewing cocoa leaves vs. snorting the crystalline powder. He also issues strong warnings on Datura (Jimsonweed), has cautionary advice on marijuana & makes salient remarks about cultural relativism in relation to all drugs. A surprising inclusion is an essay on Uri Geller in which Weil is seen 1st as convinced believer--until he spends a day with the Amazing Randi. Still, he likes to believe there's Something There...So, unabashed advocacy of transcendent union, with some sophisticated observations on drugs & cultures.--Kirkus (edited)