The concept of software craftsmanship has roots in the earliest days of computing but has received comparably little attention from the research community.As a reaction to how Agile methods were practiced and taught in industry, in 2009, the Manifesto for Software Craftsmanship was formulated and published, drawing attention to the concept. Subsequent books and research papers have also elaborated on the concept. With this dissertation, we aim to study the software craftsmanship phenomenon using empirical software engineering methods.We developed an anatomy of software craftsmanship through a systematic literature study and a longitudinal case study, following a project consisting of multiple teams over several years.We also illustrate some consequences of not following through on the espoused craftsmanship practice of managing and account for technical debt. We find that some areas exhibited high growth in technical debt, while others remained comparably idle. This indicates that it is important to keep track of existing technical debt, but repayment should consider the distribution of each kind of technical debt in the codebase. Our studies are empirical, using mixed methods, analyzing quantitative as well as qualitative data.We used thematic coding to structure the qualitative data into themes, principles, and practices. We provide our systematically derived anatomy of the principles and practices of software craftsmanship and discuss how these relate to other principles within software engineering in general.