This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book examines the research in post-existentialism in the psychological therapies in relation to ideology and inter-subjectivity, questioning whether post-existentialism could enable a return to giving a primacy to practice. It argues that a way of approaching post-existential practice is illustrated through the idea that relationships occur in the between, which is largely unknown, except as suggested by Laing, through experience. The book provides a re-examination of the case of Lola Voss and also explores some implications of post-existentialism for counselling psychology, with a particular focus on diagnostic categories. It explains research in the psychological therapies, in terms of changing notions of intersubjectivity. The book suggests that a very different type of research could contribute to a way of exploring meaning, influenced by post-existentialism, which could open a challenge to the ideological assumptions behind values.