Jan Oscar Sverre Lucien Henri Guillou was born in 1944 in Sodertalje, Sweden. He is a Swedish journalist and writer, who has gained international fame with his spy novels.
Guillou published his first book when he was 27. He is most famous for his Hamilton series which began with his 1986 nove Coq Rouge.
After finishing the Coq Rouge series, Guillou wrote a trilogy about Arn Magnusson, a fictional Swedish character from the Middle Ages forced to become a Knight Templar. The series is an account of the life of Arn Magnusson, a fictional character who becomes a witness as well as a catalyst to many important historical events, both in his homeland of Sweden and in the crusades against the Middle East.