Readable, well organized, and easy to use, this outstanding encyclopedia signifies a timely and major advance in providing in-depth and comprehensive coverage of medical genetics for the lay reader. The two volumes include nearly 400 substantive entries on genetic diseases and conditions as well as information on basic genetics concepts such as DNA, chromosomes, genetic testing, and pedigree analysis and construction (genetic family history). An advisory board of seven distinguished genetics specialists (clinical geneticists and genetic counselors) oversaw the accuracy of the text, which is authored by an international slate of clinicians, genetic counselors, and medical writers. Each of the alphabetically arranged entries follows a standard format definition, description, genetic profile, demographics, and signs and symptoms designed to answer the questions healthcare consumers actually ask. In addition, entries provide citations for further reading, contact information for support and advocacy organizations, and recommendations for notable web sites. Cross references for subjects without entries are interspersed throughout the work and are easy to follow. The key terms box that appears in select entries and provides succinct and understandable definitions is especially noteworthy. Other special features include a comprehensive glossary, a chromosome map, a guide to symbols for pedigree charts, and an organizations directory all features that should make understanding difficult genetics concepts much easier. The Encyclopedia of Genetic Disorders and Birth Defects (Facts On File, 2000. 2d ed.) has long been the authoritative title for this subject and should remain on the shelf. However, larger consumer health collections and those that frequently receive requests for consumer information on clinical genetics are advised to purchase this as a supplement; it is worth every penny. Highly recommended.