The second edition of the book Introduction to Adult Psychopathology is a revision of the first edition based on changes in modern diagnostic systems, as well as more recent scientific findings. This essential and comprehensive psychopathology manual initially addresses concerns related to the definition of psychopathology, including historical, social, and cultural dimensions. Epistemological issues related to the study of psychopathology are examined, as well as research methods and assessment methods. The main contemporary classification systems DSM-5 and ICD-10 are then described, and similarities and differences are noted in relation to the previous DSM-IV system, as well as the ICD-11 which is expected to be published in the future. A historical overview of the study of psychopathology from antiquity to the present follows. Each basic approach regarding etiology and intervention is described, including psychological approaches (psychoanalytic, cognitive, behavioral, family, existential), as well as the biological and socio-cultural approach. The following chapters cover the entire range of adult mental disorders. Anxiety disorders, obsessive-compulsive and related disorders, disorders related to trauma and stressors, depressive disorders, bipolar and related disorders, disorders in the schizophrenia spectrum and other psychotic disorders, dissociative disorders, psychophysiological-psychosomatic disorders, somatic symptom disorders and related disorders, sexual dysfunctions, gender dysphoria, paraphilic disorders, feeding and eating disorders, personality disorders, substance-related disorders, addictive disorders, and organic syndromes are examined. Reference is made to both the clinical picture of each syndrome-disorder with clinical examples and to the socio-cultural components, epidemiological data, and research data based on the most recent research studies, as well as to etiology and intervention according to each theoretical approach. The extensive bibliography at the end of the book covers key aspects of the topics and research in the field of psychopathology. The manual is aimed at students and mental health professionals, such as psychologists, psychiatrists, social workers, etc. However, its simple and understandable writing style makes it accessible to the general public who would like to delve into the topics of psychopathology.