60th Anniversary Edition
A strange sea monster suddenly appears on the lake ...a fortune is unearthed from an old cannon ... a valuable dinosaur egg is stolen.
Who's responsible? Those seven junior geniuses - and their wild ideas!
"Every time you Mad Scientists get mixed up in something, it means trouble!" cries the mayor of Mammoth Falls.
Watch out as the seven junior geniuses of the Mad Scientists' Club turn the town upside down.
Fully illustrated with classic Charles Geer drawings.