Background: Psychotherapy manuals are critical to the dissemination of psychotherapy treatments. Psychotherapy manuals typically serve several purposes, including, but not limited to, establishing new psychotherapy treatments, training providers, disseminating treatments to those who deliver them, and providing guidelines to deliver treatments with fidelity. Yet, the proliferation of psychotherapy manuals has not been well-understood, and no work has aimed to assess or review the existing landscape of psychotherapy manuals. Little is known about the breadth, scope, and foci of extant psychotherapy manuals. Objective: This scoping review aims to identify and explore the landscape of existing book-based psychotherapy manuals. This review aims to specify the defining characteristics (ie, foci, clinical populations, clinical targets, treatment type, treatment modality, and adaptations) of existing book-based psychotherapy manuals. Further, this review will demonstrate how this information, and psychotherapy manuals more broadly, has changed over time. This project aims to make a novel contribution that will have critical implications for current methods of developing, aggregating, synthesizing, and translating knowledge about psychotherapeutic treatments. Methods: This scoping review will review book-based psychotherapy manuals published from 1950 to 2022.This scoping review will be informed by guidance from the Joanna Briggs Institute Scoping Review Methodology Group and prior scoping reviews. Traditional search and application programming interface-based search methods will be used with search terms defined a priori to identify relevant results using 3 large book databases: Google Books, WorldCat, and PsycINFO. This review will leverage machine learning methods to enhance and expedite the screening process. Primary screening of results will be conducted by at least 2 authors. Data will be extracted and double-coded by research assistants using an iteratively defined codebook. Results: The search process produced 78,600 results, which were then iteratively deduplicated. Following deduplication, 50,583 results remained. The scoping review is expected to identify common elements of psychotherapy manuals, establish how the foci and content of manuals have changed over time, and illustrate coverage and gaps in the landscape of psychotherapy manuals. Results from this scoping review will be critical for future work focused on developing, aggregating, synthesizing, and disseminating knowledge about psychotherapeutic treatments. Conclusions: This review will provide knowledge about the vast landscape of psychotherapy manuals that exist. Findings from this study will inform future efforts to develop, aggregate, synthesize, and translate knowledge about psychotherapeutic treatments. International Registered Report Identifier (IRRID): DERR1-10.2196/47708
