Book excerpt: Recent advances in catalytic methods based on earth-abundant metals are discussed. Catalysis with earth-abundant metals, often referred to as base metals, is having a transformative impact on synthetic chemistry. Research in this area is driven not only by the common interest in the sustainability of chemical synthesis but also by the vast opportunity to discover and develop novel reaction chemistry that is not attainable with rare and precious metal catalysts. This work provides representative developments in base-metal catalysis, specifically catalysis with 3d-transition metals, in a format suitable for practitioners of organic synthesis. Volume 2 is focused on recent advances in catalysis involving cobalt, iron, manganese, and chromium. Topics covered include various types of cross-coupling processes, hydrofunctionalization of alkenes and alkynes, C-H functionalizations, and catalytic Nozaki–Hiyama–Kishi-type reactions.