The second edition of The Cytogenetic Symposia, published in 2005, consists of an introduction, briefly outlining the development of the practice of cytogenetics, from the seminal work of Tijo and Levan in 1956 to the current partnership of cytogenetics and molecular genetics. The succeeding chapters, written by cytogenetic technologists, PhDs, and medical doctors from the United States and Canada, provide up-to-date information on a broad range of topics in both cytogenetics and molecular cytogenetics. Many chapters now include molecular information reflecting the increased recognition of diagnostic complementation of these arenas. Each chapter includes a set of multiple choice questions, and most chapters contain a glossary. The answers for chapter questions have been placed in an appendix. The intent of the Cytogenetic Symposia is to offer a thorough, but condensed overview of the field. This publication is an excellent resource for individuals preparing for the cytogenetics certification examination. Use of references cited in each chapter will lead interested parties to more detailed information.