This book explores the complex and diverse issues of psychotherapy, with a specific focus on peculiar aspects common to all approaches despite the vast number of therapeutic schools that have emerged over time-more than 250 worldwide. While each approach can be traced back to a handful of core psychological models (such as cognitive psychology, psychoanalysis, humanism, and behaviorism), many schools have developed their own unique variations based on individual insights or the need to address specific psychological issues. The rise of eclectic approaches further complicates the field, often favoring practical convenience over strong theoretical or clinical foundations. The book highlights a major issue by presenting chapters that explore various aspects of the psychotherapeutic approach. It covers broad, cross-cutting themes such as psychedelic-assisted therapy, common relational dynamics in psychotherapy, and the influence of clients’ mental models on treatment outcomes. The second section will focus on specific clinical issues: eating disorders in Western societies and intervention models applied in complex organizational settings. Rather than adopting a rigid verificationist approach to validate theoretical models, the book presents diverse practical considerations from professionals in the field, encouraging readers to critically evaluate the effectiveness of different therapeutic models.