Jan Olof Lennart Olsson (pen name Jolo) (31 March 1920 Stockholm, Sweden — 30 April 1974, Hjärnarp, Skåne) was a popular Swedish writer and a journalist for the Swedish newspaper Dagens Nyheter where he elevated the short sketch to an art.
He was married to Margareta Sjögren, a journalist at another Swedish newspaper.
Olsson is most known for his books about World War I and World War II, in Swedish named Den okände soldaten (1965; The unknown soldier) and Någonstans i Sverige (1974; Somewhere in Sweden), and several essays on popular history has been issued as books.
He also wrote a large number of travel books.
In both fields his real strength lies in his ability to use vivid and picturesque situations to illustrate general patterns.