<P>Scientists estimate that, until 1900, the water level of the Chesapeake Bay rose at the rate of three feet every thousand years. Alarmingly enough, the bay rose by one foot in the twentieth century alone, and for evidence of this dramatic change one need only observe the effects of rising water on the islands of the Chesapeake Bay, which slowly are slipping from sight.</P><P>A retired oceanographer who first conducted research on the bay in the 1950s, William B. Cronin here supplies a survey of the changing fortunes of these forty-odd islands, from Garrett in the north to Gwynn and James islands to the south. Cronin's historical and scientific tour outlines their erosion, their loss of marshland, and the rich if changing human experience they have supported for generations. He draws on imagery that includes the work of celebrated local photographer A. Aubrey Bodine, colonial and state records, newspaper pieces, and his own personal and professional experience.</P><P>Historic nautical charts, compared to current data from the National Oceanographic and Atmospheric Administration, leave no doubt of the crisis many of the islands face. On one, Holland, rising water in the late 1910s forced townspeople to move their houses by barge to the mainland. On another, Barren, a sizable hunting lodge housed guests as late as the 1970s but by 1985 had become a wreck beneath the water. An appendix documents the many small islands that have dropped entirely from view since the seventeenth century.</P>