The rapid progress in genetic research, including the completion of the Human Genome Project, made a new edition of The Gale Encyclopedia of Genetic Disorders a necessity. Compiled by genetic counselors, physicians, and medical writers, the encyclopedia explains genetic and congenital disorders in lay language. The 400 alphabetical, signed entries cover genetic disorders ( Down syndrome, Sickle cell disease); congenital disorders ( Cleft lip and palate, Patent ductus arteriosis); scientific concepts and research (Chromosome, Human Genome Project); and clinical specialties and tests ( Amniocentesis, Genetic counseling). There are also articles about conditions, such as Prion diseases, which have a genetic component but can be transmitted between unrelated individuals, and Accutane embryopathy, a combination of birth defects that occurs when a pregnant woman takes the drug Accutane.The entries are from 500 to 4,000 words long. They provide a definition of the subject, a description of the disorder, a genetic profile, and information on demographics, signs and symptoms, diagnosis, treatment and management, and prognosis. Color boxes have definitions of key terms. The articles also have resource lists. More than 200 illustrations, including color photographs and pedigree charts, supplement the text. A symbol guide for the pedigree charts and a list of entries appear in the front of each volume. Gene maps, a glossary, a list of organizations, and an index complete the work. There are ample boldface cross-references within the articles.The new edition is 218 pages longer than its predecessor. All of the entries have been updated and revised. The broad scope of the encyclopedia makes it a very useful resource. The second edition of the Encyclopedia of Genetic Disorders and Birth Defects (Facts On File, 2000) has a nice history of human genetics, but its entries on the disorders are quite short. The Genetic Disorders Sourcebook (2004) and the Congenital Disorders Sourcebook (1997) from Omnigraphics cover only the more common disorders. Public libraries and consumer - health collections will find The Gale Encyclopedia of Genetic Disorders well worth the price.