Modern binoculars and scopes meet a variety of user needs. This Field Guide provides readers with a concise, organized reference that explains the functions and configurations of instruments commonly used by bird watchers, hunters, amateur astronomers, and military and law-enforcement members. This book also addresses the rationale behind instrument design choices, with hardware examples illustrating specific arrangements and features.

The intent of this Field Guide is to explain the functions and configurations of various types of binoculars and scopes to the beginner as well as to the experienced user. We also attempt to show why a given instrument is designed the way it is.

Binoculars of various sizes - ranging from pocket size to giant models, high magnification and wide angle types, and ones used for military, law enforcement, marine and amateur astronomical applications - are considered. Scopes include small monoculars, spotting scopes, riflescopes, weapon sights, and astronomical types as large as 300 mm. Mounts for the larger instruments are also considered. Theoretical explanations of optical and mechanical systems performance are summarized.

We acknowledge with thanks Bushnell Outdoor Products, Carl Zeiss AG, Carl Zeiss Sport Optics, Leuopold & Stevens, Möller-Wedel GmbH, Questar, Schultz Loupe Direct, Steiner, Swarovski Optik KG, and the University of Arizona's College of Optical Sciences for technical information and illustrations included here.

We also thank John Greivenkamp, Wright Scidmore, and Bruce Walker for reviewing the manuscript and offering valuable suggestions for corrections and clarifications.

Any mention of specific hardware in this Field Guide is not meant to be an endorsement, but rather, it is intended to cite an example of a certain instrument configuration or design feature of potential interest to the reader.

The authors dedicate this Field Guide with love to the memory of Paul's late wife, Betty, and to Daniel's wife, Suzanne.