This is a collection of Harald Cramér's extensive works on number theory, probability, mathematical statistics and insurance mathematics. Many of these are not easily found nowadays in their original sources, for instance his pioneering works on risk theory published in jubilee volumes of the Skandia Insurance Company in 1930 and 1955. Despite their age, these eminent examples of Cramér's expository style remain highly readable. Cramér (Stockholm 1893-1985) was one of the "fathers" of modern mathematical statistics. His famous book on the subject is still an important reference. His statistical papers included here were seminal to the subsequent development of the subject. The collection includes a complete bibliography of Cramér's work.