This book examines the fundamental issues of Marxism in the 21st century and explores its contributions through the explanatory framework of the unity of continuity and stages, spatial and temporal analysis, and the dialectical relationship of universality and particularity of Marxist historical development. Marxism in the 21st century is a concept closely related to the historical changes of capitalism and the historical shift of the centre of the socialist movement. Marxism in the 21st century should be developed on the basis of the continuation of the fundamental position, value orientation, ideals and beliefs, basic principles and methodological principles of Marxism. This book explores the logic of the development of modernisation in contemporary China and the world, the communication and interaction between contemporary China and the world, and the coexistence of socialism and capitalism. It also examines the relationship between the adaptation of Marxism to the Chinese context, Marxism in contemporary China and in the 21st century. The book also discusses Xi Jinping's Thought on Socialism with Chinese Characteristics for a New Era, which provides a scientific theoretical system for interpreting the contemporary world and could become the core theoretical form of Marxism in the 21st century. The book will be essential reading for students and scholars of Marxism, Chinese studies and modernisation theory.