It is perhaps because of this perceptive quality of understanding that Larry’s report of the survey has readily adapted into a popular field guide, directing the curious into a fascinating exploration of the “heap o’ living” going on under our very noses and all but ignored by most of us. This guide is not intended as an exhaustive research work or a listing of all the living things to be found on Castle Neck. Rather, it purposely addresses itself to natural history readily observable by visitors with sharp eyes and reasonable patience. When a rarity is included like the Ipswich Sparrow, it is only to indicate that such unusual thrills await the discoverer—occasionally! [Illustration: Deer Tracks in the Sand.] While this guide serves as a reminder to those engaged in the study of ecology that this is a rich area for serious investigation, the amateur naturalist or the casual beach visitor, primarily on hand to sun, swim, or picnic, may use it to make his stop on the Neck more meaningful. Knowing, for instance, that Hog Island is a drumlin (a pile of debris deposited in the Great Ice Age) adds enormous interest to the surroundings. Larry’s guide is compiled with the understanding eye and heart of an able and enthusiastic young naturalist. It invites you to look over his shoulder as he investigates his finds, and tempts you to further exploration on your own. The analysis of the infinitely complex relationships of living animals and plants to their environment, and to one another, is a relatively new science. People with a strong desire to know more about the great sea of life surrounding them have a real opportunity to contribute valuable observations to ecological knowledge. You may very well be one of these! Bradford Washburn Director Museum of Science Boston, Massachusetts ACKNOWLEDGMENTS The author is first and foremost indebted to Mr. and Mrs. Cornelius Crane for their unfailing interest in the preparation of this field guide, and to members of the Museum staff who collaborated to edit and produce it. Among these were Norman D. Harris, Director of Education, Gilbert E. Merrill and Chan Waldron of the Education Department, Miss Caroline Harrison, Director of Public Relations, and Mrs. Christina Lopes and Mrs. Margaret Jordan of her department. Invaluable also in preparation of the manuscript was the careful final editing of Miss Helen Phillips, Houghton Mifflin Company. Especially is the author grateful to the following for advice and comment on various chapters: Clifford S. Chater, Assistant Professor, Entomology and Plant Pathology, Waltham Field Station; Dr. Norman A. Preble, Mammalogist, Northeastern University; J. Phillip Schafer, Geologist, U. S. Geological Survey; Colonel E. S. Clark, Curator of Marine Life, Peabody Museum of Salem, and Dr. Stuart K. Harris, Department of Botany, Boston University.