Preface

       The enduring goal of scientific endeavor, as of all human enterprise, I imagine, is to achieve an intelligible view of the universe. One of the great discoveries of modern science is that its goal cannot be achieved piecemeal, certainly not by the accumulation of facts. To understand a phenomenon is to understand a category of phenomena or it is nothing. Understanding is reached through creative acts.

      A. D. HERSHEY

       Carnegie Institution Yearbook 65

      All five editions of this textbook have been written according to the authors’ philosophy that the best approach to teaching introductory virology is by emphasizing shared principles. Studying the common steps of the viral reproductive cycle, illustrated with a set of representative viruses, and considering mechanisms by which these viruses can cause disease provides an integrated overview of the biology of these infectious agents. Such knowledge cannot be acquired by learning a collection of facts about individual viruses. Consequently, the major goal of this book is to define and illustrate the basic principles of virus biology.

      In this information-rich age, the quantity of data describing any given virus can be overwhelming, if not indigestible, for student and expert alike. The urge to write more and more about less and less is the curse of reductionist science and the bane of those who write textbooks meant to be used by students. In the fifth edition, we continue to distill information with the intent of extracting essential principles, while providing descriptions of how the information was acquired and tools to encourage our readers’ exploration of the primary literature. Boxes are used to emphasize major principles and to provide supplementary material of relevance, from explanations of terminology to descriptions of trailblazing experiments. Our goal is to illuminate process and strategy as opposed to listing facts and figures. In an effort to make the book readable, we have been selective in our choice of viruses that are used as examples. The encyclopedic Fields’ Virology [Knipe DM, Howley PM (ed). 2020. Fields Virology, 7th ed. Lippincott Williams & Wilkins, Philadelphia, PA] is recommended as a resource for detailed reviews of specific virus families.

      What’s New

      This edition is marked by a welcome addition to the author team. Our new member, Theodora Hatziioannou, brings expertise in retrovirology, entry, and intrinsic immunity, as well as authority regarding ancient Greek mythology and philosophy that the attentive reader will see is generously sprinkled throughout the text.

We have added an important new chapter in Volume II, “Therapeutic Viruses.” While the majority of the chapters define how viruses reproduce and cause mayhem to both cell and host, this new chapter turns the tables to discuss how viruses can be beneficial to eliminate tumor cells, deliver therapeutic genes to specific cells, and expand our arsenal of vaccines for prevention of virus-mediated diseases.

      The authors continually strive to make this text accessible and relevant to our readers, many of whom are undergraduates, graduate students, and postdoctoral fellows. Consequently, for this edition, we enlisted the aid of more than twenty of these trainees to provide guidance and commentary on our chapters and ensure that concepts are clearly explained and that the text is compelling to read. This unique group of editors has been invaluable in the design of all of our fully reworked and up-to-date chapters and appendices, and we extend a particular thank-you to them for sharing their perspectives.

      A new feature is the inclusion of a set of study questions and/or, in some cases, puzzles, as aids to ensure that the key principles are evident within each chapter. This section complements the Principles that begin each chapter, focusing on unifying core concepts.

      Finally, although the SARS-CoV-2 pandemic began as we were preparing to go to press, we have included additions to relevant chapters on the epidemiology, emergence, and replication of this global scourge, as well as some hopeful information concerning vaccine development. What is apparent is that, now more than ever, an appreciation of how viruses impact their hosts is not just an academic pursuit, but rather literally a matter of life and death. We extend our gratitude to all those who serve in patient care settings.

      Principles Taught in Two Distinct, but Integrated Volumes

      Volume I covers the molecular biology of viral reproduction, and Volume II focuses on viral pathogenesis, control of virus infections, and virus evolution. The organization into two volumes follows a natural break in pedagogy and provides considerable flexibility and utility for students and teachers alike. The two volumes differ in content but are integrated in style and presentation. In addition to updating the chapters and appendices for both volumes, we have organized the material more efficiently, and as noted above, added a new chapter that we believe reflects an exciting direction