This is actually a bilingual book, as the text is written both in Finnish and in English. However, the text is not very detailed, as the main emphasis is on the photographs. There are about 200, mainly of the Finnish Navy, but also about the other vessels in Finnish waters: German, Soviet and Italian. Surprisingly many of them are of submarines, perhaps something like 20% of all photos of the book. The book includes several tables by Per-Olof Ekman showing the technical statistics (length, weight, weapons, etc.) of the Finnish, Soviet and German ships in the Baltic Sea. The photos are chosen well, as they are very good and clear. Some of them also show submarine crews and captains. There are also photos showing the laying of an anti-submarine net across the Gulf of Finland in 1943. This net stopped the Soviet submarines for over a year despite several breakthrough attempts and severe air and sea attacks. Kalevi Keskinen has written over 20 books about the Finnish Air Force, but this is his first one about the Navy. A good book if you are looking for good photos, and the English text also opens the book for non-Finnish readers.