"The High School Boys' Training Hike" by H. Irving Hancock within the "High School Boys" series. However, given the nature of the series that focuses on the adventures, camaraderie, and sporting experiences of high school boys, it's possible that such a title might be part of the series, but I don't have specific details or publication information about this particular book in the series.The series typically involved various outdoor activities, sports, and adventures undertaken by the high school boys of Gridley High School. If "The High School Boys' Training Hike" is indeed a part of the series, it might portray the boys going on a hiking expedition or an outdoor adventure that involves training and challenges.H. Irving Hancock's "High School Boys" series was popular among young readers for its portrayal of outdoor activities, camaraderie, and the values of teamwork, adventure, and friendship among the characters. These stories often depicted the thrill of outdoor pursuits and the strong bonds formed among the boys in the series.