A picaresque novel about Allan Karlsson, who decided that he did not want to attend his hundredth birthday party at the old-age home where he was staying so he decided to leave, with no particular plan for what he was going to do.
He has various improbable adventures, and the story is told with a series of flashbacks to his life story. He was a self-taught explosives expert, and as such had played a minor but significant part in various world events, learning several languages along the way and earning the gratitude of several powerful politicians.
I read it mainly because I had seen a film based on the book which I had enjoyed, and from what I could remember of it the film seemed to adhere quite closely to the book.
While it is primarily a picaresque novel, the story seems to overlap several other genres. On one level it is a crime novel, a police procedural, though also with a lot of incompetent bumbling — in the film version it is more like The Lavender Hill Mob than a serious whodunit. But perhaps these are all part of the picaresque genre anyway.