New cures for cancer and AIDS are waiting to be discovered in the world's rain forests, and we had better find them quickly before they disappear, says Joyce. This is the mission of the ethnobotanist, as described by the author, science correspondent for National Public Radio. Ethnobotanists encounter the perils of the jungle and the alien customs of indigenous peoples in order to find plants that may yield therapeutic drugs. Plants can be thought of as miniature chemical factories; with millions of years of evolution and millions of species, nature's vast creativity has undoubtedly invented chemical compounds that can cure human ailments. Shamans in many cultures have successfully treated people with native plants. The first westerners to venture deep into the rain forests in the 1800s to find medicinal plants returned with specimens that led to curare and quinine. Joyce provides a vivid historical account of those early days, a Golden Age of intrepid and colorful personalities. But by the 1970s ethnobotany was entrenched in a period of dormancy as drug companies, realizing that thousands of plants had to be studied to yield one useful drug, shifted their efforts to synthesizing drugs in the laboratory. Only in the last few years has the field experienced a renaissance. Ethnobotanists are now scattering across the globe to prospect for plants. Joyce accompanied one such expedition into the rain forest of eastern Ecuador. He experienced for himself the many dangers faced by ethnobotanists, including poisonous snakes and political turmoil. Knowing that thousands of rain forest species disappear each year as civilization extends its reach, ethnobotanists are battling not just to find drugs, but to preserve the rain forest's incredible biodiversity by showing that it has economic value. For the most part this book is informative and entertaining. But the narrative is often chaotic, leading the reader astray from the main focus with endless mind-numbing details.