On the maps of the world for a long time, the vast expanses of North Western America, the coasts of the Arctic Ocean and the regions of the Far East remained white spots. In the XVII-XVIII centuries. the heroic campaigns of Russian explorers, sailors, expeditions of the Academy of Sciences, ships of the Russian Navy made it possible to study in detail the little-explored territories. The discoveries made were a true conquest of geographical science. The history of these great discoveries is devoted to the book of A.V. Efimov, the author of famous historical and geographical works, who was awarded the S. Dezhnev Prize of the Geographical Society of the USSR for outstanding works in the field of geographical sciences. The work is based on numerous documents, it uses materials from cartographic collections of Soviet archives and takes into account the latest scientific research. The book is designed for wide circles of readers