This updated Third Edition reflects dramatic improvements in the techniques and instrumentation for performing in situ polymerase chain reaction (PCR) studies. It includes a greatly simplified, one-step protocol for reverse transcriptase (RT) in situ PCR; a revised and simplified start-up protocol for in situ PCR; and additional protocols for in situ hybridization and PCR in situ hybridization. Readers will also find current studies that demonstrate the power of in situ PCR as a tool for detecting HIV-1, human papillomavirus, hepatitis C, and cancer.A complementary video program -- Key to Successful in situ PCR -- demonstrates in situ PCR techniques step by step. See Media Section for details.