This book provides for the practicing pathologist and the researcher the information which is necessary to make decisions regarding the incorporation of immunohistochemical, cytometric and molecular biologic tests into clinical practice. In the early chapters, the book introduces basic biological principals that are useful in putting these methods into context, such as the functions of oncogenes and tumour suppressor genes and the structures of antigens used in diagnostic pathology. In the next few chapters, the basic methods of immunocytochemistry, in-situ hybridization, Southern blotting, PCR and other methods are presented, together with well-validated protocols that may be used in the clinical laboratory. In the third part of the book, an organ-system based exposition of common diagnostic issues is presented, which incorporates cytogenetic, molecular biological, immunohistochemical and cytometric information. In addition, selected protocols are provided. This information is presented in a way that allows the clinician to know what types of testing are clinically appropriate given current information and for the basic researcher to understand what is known (and not known) about the diseases presented.