To make sense of data and use it effectively, it is essential to know where it comes from and how it has been processed and used. This is the domain of paradata, an emerging interdisciplinary field with wide applications. As digital data rapidly accumulates in repositories worldwide, this comprehensive introductory book, the first of its kind, shows how to make that data accessible and reusable. In addition to covering basic concepts of paradata, the book supports practice with coverage of methods for generating, documenting, identifying and managing paradata, including formal metadata, narrative descriptions and qualitative and quantitative backtracking. The book also develops a unifying reference model to help readers contextualise the role of paradata within a wider system of knowledge, practices and processes, and provides a vision for the future of the field. This guide to general principles and practice is ideal for researchers, students and data managers.