One if by Sweden, and one in Berlin:
This fondly recalled tale of youthful intrigue was well liked due to the friendships between Bill, his friend Anders, and their object of friendly rivalry, childhood sweetheart, Eva-Lotta. The details of the story have long since faded from memory, but I can faintly recall supporting characters like Sixten, Policeman Bjork, and Commissioner Strand 35 years later. The protagonists show resourcefulness in overcoming adversity and have a lot of fun in the process. By Astrid Lindgren.
(Out of print/costly but available online)
Erich Kästner’s classic tale of a boy and his friends’ collective effort to reclaim stolen money is nothing short of pleasurable. Emil goes traveling on a train, and later embarks on a quest for justice! His adventure is a lot of fun, as he and his friends demonstrate the value of teamwork, friendship, and camaraderie. Be sure to get the right edition: If you are an adult reader, an older edition will contain original names and classic language (not difficult to read), but if you are a young American, the modern language may not seem out of place.