The Introduction begins by laying out the methodological and theoretical foundations of the book. It explains that, currently, religious studies research on this topic has been limited, only conducted on select aspects such as mindfulness practices. Methodologically, ethnographic observation and interviews add significant texture to historical and discourse analysis and reveals the full diversity of ways therapists have related to Buddhist traditions. Further, at a theoretical level, previous studies often present binary interpretations of psychotherapists’ approaches to Buddhist traditions as either cases of secularization or religious transmission. These totalizing interpretations do not take account of research on the social construction of classifications of the religious and not-religious (the secular, science, medicine, etc.). The Introduction then outlines six major sets of approaches that clinicians have taken to Buddhist traditions: clinicians (1) therapize, (2) filter, (3) translate, (4) personalize, (5) adopt, and (6) integrate those aspects of Buddhist traditions that they view to be religious. These categories, though highly artificial, are a useful method for mapping therapists’ approaches to Buddhist traditions because they illustrate how they arise out of the relational configurations clinicians believe they make between the religious and the not-religious. And yet, these configurations always prove unstable.