This book provides an accessible introduction to Marx’s seminal work Das Kapital and explores some of the core ideas of Marxian political economy relevant for modern day economies. It brings together a mixture of historical and contemporary perspectives on the implications of Marxian political economic analyses of capitalism. Chapters in the book cover a broad range of topics in Marxian political economy, and more specifically Marx’s theory of value. The first section of the book gives an overview of Das Kapital, providing a historical background and making the authors’ original thinking in the methodologies of Das Kapital and the Marxism/Neo-Ricardianism debate available in English for the first time. This section also introduces readers to an important discussion of productive versus unproductive labour. The second part of the book discusses the application of these ideas to some understudied questions of measuring surplus value, including the reconstruction of national income accounts and input-output tables, and the role of the welfare state and social wage. The final part of the book sets forth new research in Marxian analysis in the 21st century, facing the challenges brought about by digital technology, digital labour, lean production and the long-run recessionary state of the global economy. This book will be of interest to scholars of Marxist economics and political economy, as well as related areas in the history of economic thought, sociology and political science.