Molecular pathology explores how changes at the DNA, RNA and protein level cause disease and how those alterations can be detected and interpreted. It sits at the intersection of genomics, diagnostics and personalized medicine, transforming how diseases are classified and treated. This book surveys contemporary molecular methods—PCR variants, next-generation sequencing, in situ hybridization, and proteomic assays—and explains their clinical applications. Emphasis is placed on assay design, quality control, result interpretation and the pitfalls that can mislead diagnostics. Case vignettes illustrate how molecular data refine diagnosis, prognostication and therapeutic selection, especially in oncology and inherited disorders. The volume is written for laboratory scientists, pathologists and clinicians seeking a practical, up-to-date reference on implementing molecular testing.