This completely revised and updated edition takes advantage of the many new developments and applications that have occurred in PRINS and in situ PCR technology, including a new fast multicolor PRINS method for identifying human chromosomes, PRINS protocols for in situ detection of unique sequences and point mutation analysis, a new dideoxy PRINS procedure, and in situ PCR and PRINS protocols for plants. The authors describe in detail various applications of PRINS in human (detection of gene deletions in cancer detection of fetal cells in maternal blood, and assessment of aneuploidy in brain tissues and embryos) as well as plant cells. Readily reproducible in situ PCR techniques are also presented for the detection of cytomegalovirus, and for use in combination with microdissection. In situ RT-PCR techniques are also given for use in plant or cancer investigation.