This document discusses psychiatric classification systems and the Diagnostic and Statistical Manual of Mental Disorders (DSM). It provides an overview of the history and evolution of the DSM from 1952 to the current DSM-5 published in 2013. The number of disorders and pages in each edition of the DSM has increased over time. Early editions were based on psychoanalytic concepts while later versions use a neo-Kraepelinian approach emphasizing clinical description and validity. Key changes in the DSM-5 include dimensional assessments, elimination of the multi-axial system, and expanded criteria for certain disorders. The document also briefly discusses the International Classification of Diseases used for mental illness diagnosis.