First diagnosed in 1975, Lyme disease is an infection that is spread to humans and other animals by infected deer ticks; if left untreated, it can cause serious medical problems. Landau describes the disease's puzzling history, including symptoms, current research, means of protection against infection, efforts to develop vaccines for humans and pets, and pesticides to eliminate the tick. Clear, well-chosen photos add drama--especially in the several close-ups of the ticks. This ""First Book"" is a useful blend of science and medicine, with a readable text on a timely topic. Glossary; further reading; index.