The genera Martes, Pekania, Gulo, and Eiraform a distinct lineage known as the ‘Martes Complex’. A recent re-evaluation of the genus Martes created a need to synthesise the current state of knowledge of the Martes Complex. This book provides an overview of the biology and ecology of species in the Martes Complex, while establishing an empirical basis for exploring the complexity of these fascinating species in more detail. In this book, 45 scientists from 10 countries contributed 14 chapters describing issues related to the Martes Complex, including both single-species and comparative analyses. The book is organised into 4 sections. Part I considers the natural history of the Martes Complex; Part II concentrates on the conservation and management of species; Part III focuses on habitat ecology; and Part IV on research techniques. The book also focuses on knowledge gaps for neglected species, and presents new findings and syntheses on the ecology and status of several poorly known species.