Where can one find a succinct but thorough reference, handy in its format, but accessible in its style, for the current information about a genetic disorder? This catalogue gives the reader a summary of seemingly innumerable clinical entities, but even more important, a list of diagnostic criteria, tips on management, and information about whether the gene has been mapped or cloned, current and relevant primary sources and references, and parent-or disease-specific support groups. This material is invaluable and should be in the hands of every practitioner!