Based on an exhibition series hosted by the Hamburger Bahnhof contemporary art museum in Berlin over a period of two and a half years, the book is the first ever overview of the collection in all its diversity. Its chapters are headed by the letters of the alphabet, and address representative ideas, individual positions, significant historical exhibitions and artistic genres of the 1960s and 70s. The first chapter, for instance, offers insights into the Italian Arte Povera movement, while chapter Handlung (action) discusses the performative aspects of art; and the part of the book entitled Kubus (cube) focuses on geometrical forms in minimalism. All chapters are prefixed by short texts, such as the seminal essay Escape Attempts by the American curator and critic Lucy Lippard. With its wealth of material and key works, texts and documents, this book is a new and essential work of reference.