'This book brings back memories of the great Alex Rich, a pioneer in molecular biology. He was friend, a mentor and a colleague who contributed greatly to the understanding of living processes and molecular structures.'This book is intended for students and general readers who are interested in the structures of biological molecules and history of science. The center of gravity of Alexander Rich's work is on nucleic acids and their structures and their roles in biology, but the breadth of his work is nearly unparalleled. Alex Rich published important early discoveries on the structure and activity of RNA, information transfer (translation) from RNA to protein, the structure of ribosomes with insights into polyribosome functions, the first atomic-resolution structure of nucleic acid base pairings, and the discovery of a hitherto-unknown conformation of DNA. Many of Rich's articles also have a focus on the structure of proteins in general as well as specific proteins and some are concerned with the structure of viruses. Some of Rich's early experimental work is based on scattering of X-rays from fibers but X-ray diffraction from crystals became the dominating technique of the Cold War.This is a book full of rich history of early days of modern biology and many fundamental discoveries. Alex Rich's main focus throughout his long career was on nucleic acids. His first paper on nucleic acids, was published together with JD Watson. Two years later, Rich reported creating fibers of poly-Uracil and poly-Adenine and studied their structures by diffraction.Alex Rich's laboratory determined the high resolution crystal structures of the ApU and GpC fragments of double helical RNA from Rich's group is considered a landmark in the detailed understanding of nucleic acid structure.