In each novel, the Hardy Boys are constantly involved in adventure and action. Despite the frequent danger, the boys "never lose their nerve ... They "are" hardy boys, luckier and more clever than anyone around them." They live in an atmosphere of mystery and intrigue: "Never were so many assorted felonies committed in a simple American small town. Murder, drug peddling, race-horse kidnapping, diamond smuggling, bank robbing, kidnapping, dynamiting, burglaries, medical malpractice, big-time auto theft, even (in the 1940s) the hijacking of strategic materials and espionage, all were conducted with Bayport as a nucleus." With so much in common, the boys are so little differentiated that one commentator facetiously describes them thus: "The boys' characters basically broke down this way – Frank had dark hair; Joe was blond." In general, however, "Frank was the thinker while Joe was more impulsive, and perhaps a little more athletic." The two boys are invariably on good terms with each other and never engage in sibling rivalry, except in the "New Hardy Boys Casefiles" series.