Kitab-ı Bahriye

The Kitab-ı Bahriye (Ottoman Turkish: كتاب بحرية, lit. 'Book of the Sea') is a navigational guide written by Piri Reis, an Ottoman cartographer, corsair, and captain. He compiled charts and notes from his career at sea into the most detailed portolan atlas in existence. The Kitab-ı Bahriye combines information from a range of sources and Piri Reis' personal experience. The coast of North Africa relies little on outside sources. The book is also one of the few primary sources of information on Piri Reis.

There are two versions of the book. The first version was composed between 1511 and 1521, and presented as a gift to the sultan Suleiman the Magnificent. The second, expanded version was produced as a commission for Ottoman Grand Vizier Pargalı İbrahim Pasha, and completed in 1526.

Both versions begin with a preface and were dedicated to the sultan Suleiman. The main part of both versions is a nautical atlas to the Mediterranean Sea. Separate chapters cover different locations with corresponding portolan charts. Piri Reis says he composed an atlas with separate maps and charts because the details in any single map are limited by the space available. There are 130 chapters in the first version and 210 in the second. The chapters start at the Dardanelles and move counter-clockwise around the Mediterranean. The maps have compass roses indicating North for each page. Scale is indicated only in the textual descriptions, not with scale bars. Standard portolan symbols indicate hazards, like dots for shallow water and crosses for rocks. Written when Ottoman sailors relied on oar-driven galleys and galiots, the Kitab-ı Bahriye reflects their needs and capabilities. It gives information on coastal waters, safe harbors, hazards, and sources of fresh water.

The second version also includes a longer introduction written in verse. It offers information on storms, winds, navigating with a compass, navigating by the stars, reading portolan charts, and the oceans. It discusses recent Portuguese and Spanish voyages including the voyages of Christopher Columbus to the Americas and Vasco da Gama's discovery of a sea route to India. The description of the Americas also includes fantastical hearsay. The book offers the first detailed Ottoman description of the Indian Ocean, with special attention given to Hormuz.

The book achieved fame only after the death of its author. The known surviving manuscripts are all copies created after 1550. At least some portion of the book has been translated into English, modern Turkish, Greek, French, German, and Italian.