Enid Blyton wrote twenty-three Famous Five adventures between 1942 and 1966, but I somehow outgrew them at number seventeen and never went any further. I think it was the repetition that got to me in the end—something that I rather enjoyed about them for most of the journey because you were able to anticipate what was in store for you. But the routine that the kids would set of on a new adventure to some strange place each Summer holiday and run down a bunch of smugglers or whatever, and always there would be the mysterious stranger who would turn out to be a Police Inspector, and one of the group would go off on their own and find vital clues and one or two more would be captured by the baddies but get rescued in the end... All that really changed was the location, although they too were rather similar, and the nefarious activities of the criminals, if only marginally.
Still, it was great fun while it lasted, along with her two other mystery series aimed at other age-groups, and her Noddy books and the Naughtiest Girl in School and the Magic Faraway Tree. She sure churned them out. It was always her master plan that you grew through her works, rather than with them. It also created the oddity that the Five had annual Summer holidays twenty-three years in a row while all remaining precisely the same age. That was the mystery no one was able to solve.