We now come to another book by D. N. Trifonov and V. D. Trifonov  on history of chemistry titled Chemical Elements: How They Were Discovered. In this book we shall describe how the alphabet of chemistry has been designed and how the inquisitive mind of the researchers discovered new chemical elements, one after another. The history of chemical elements begins with their discovery. Although hefty volumes in which elements are described in detail pay very little attention to their discoveries, they are a major part of the history of human knowledge. Each element has its own “biography”, interesting in its own way. The history of the discovery of many elements has not yet been exhaustively studied and quite a number of unclear issues should be cleared by historians of chemistry. Perhaps you will be one of them…The book was translated from the Russian by O.A. Glebov and I.V. Poluyan and was first published by Mir in1982 and was reprinted in 1985. Many thanks to gnv64 for this book.CONTENTS Notice to the reader 9 Introduction 11 Part One – Elements Discovered in Nature Chapter 1 Elements Known in Antiquity Chapter 2 Elements Discovered in the Middle Ages Chapter 3 Elements of Air and Water. Chapter 4 Elements Discovered by Chemical Analysis Chapter 5 Elements Discovered by the Electrochemical Method Chapter 6 Elements Discovered by the Spectroscopic Method Chapter 7 Rare Earths Chapter 8 Helium and Other Inert Gases Chapter 9 Elements Predicted from the Periodic System Chapter 10 Two Stable Elements Which Were the Last to Be Discovered Chapter 11 Radioactive Elements Part Two – Synthesized Elements Chapter 12 Discoveries of Synthesized Elements Within the Old Boundaries of the Periodic System Chapter 13 Transuranium Elements Conclusion 252