About the book: 1964 / This book is a story about the history of Arab navigation, about medieval Arab sailors and their geographical knowledge and discoveries. The book is based on a critical analysis of the Arabic maritime encyclopedia of 1490, its author is the largest Arab theorist and practitioner of maritime affairs, Ahmad ibn Majid al-Najdi, pilot of the first Portuguese expedition of Vasco da Gama to India. Shumovsky also relies on other works of Ahmad ibn Majid an-Naji - 24 nautical poems. In addition to this material, the author of the book takes into account the data of all five treatises on maritime science by another famous Arab pilot Sulaiman ibn Ahmad al-Mahri (XVI century), the testimony of Turkish navigators and Portuguese historical chronicles, and data from contemporary Soviet and foreign literature on this issue. The information about navigation among the Arabs contained in earlier sources is briefly discussed. Based on the analysis of primary sources, the close economic and cultural interrelation of the countries of the East for many centuries before the arrival of Europeans is shown, and the presence in this regard of a developed Indian Ocean market. The author of the book proves that the Arabs were a great maritime nation of the Middle Ages. The book is written in beautiful language.