This book contributes to one of the most challenging areas of mental health: substance misuse. Its focus is on the psychopathological experiences associated with it: both the consequences of substance misuse and the existential vulnerabilities that lead to it, even if such a clear-cut distinction is rarely possible. The work brings an innovative perspective to the issue, as it draws on two scientific fields whose association has not yet been fully explored: phenomenological psychopathology and substance misuse studies. The association of these two perspectives could build a greater understanding of this important topic and be of practical help to a wide array of professionals in their clinical practice. The structure of the book is inspired by this overall perspective. Its division into three parts is designed to introduce the reader, in a stepwise manner, to the complexities of the theme, based on the latest advances in the specific literature. The broad objective of this work is therefore to offer a useful instrument for mental health clinicians, psychiatrists, psychologists, nurses, undergraduate students of these disciplines, and all substance abuse workers.