A practical and accessible guide to the complex mathematical calculations required for accurate great-circle sailing, written by the distinguished navigator and mathematician John Seaton. With clear explanations and step-by-step instructions, Seaton demystifies this challenging subject, making it accessible to sailors of all levels. Packed with charts, diagrams, and worked examples, this book is an essential companion for any sailor seeking to navigate the globe using the shortest possible routes.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it.This work is in the "public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.