Professor Fred Peeper is an eccentric and absent-minded archaeologist and scientist. He is married to Phoebe Peeper and father to Christopher "Chris" Peeper. In the second season, he is revealed as the uncle of Uriah "Uri" Peeper, son of his brother Kenneth "Ken" Peeper. Ken appears in the first and final two episodes of season two, primarily maintaining the computer system linked to the computerized Superbook.

Physically, Professor Peeper possesses long dark brown hair, a dark brown mustache, and wears thick black-framed glasses. He is one of the few characters depicted with dots for eyes. His standard attire includes a dirty white or light brown lab coat over a light blue shirt, a dark blue necktie, black pants, and black shoes.

His personality is analytical, logical, and intellectually curious, marked by introspection. He highly values knowledge and exhibits independence, often working alone in his laboratory. While generally kind and trustworthy as a mentor to Chris and Joy, he can sometimes be critical or blunt, prioritizing factual accuracy over emotional concerns. He demonstrates a conscientious insistence on preserving historical integrity during time-travel incidents involving his family, emphasizing the importance of not altering the past.

The supernatural Bible, Superbook, is discovered stored among his belongings in his home's attic, triggering Chris and Joy's initial time-travel adventure. Upon their return, Professor Peeper expresses surprise at Chris's sudden behavioral shift, including uncharacteristic apologies and compliance, though this improvement proves inconsistent.

In the second season, the Superbook is integrated into a home computer system, enabling time travel via the monitor. The central plot involves the search for the missing dog, Ruffles, who travels back to biblical times. While Professor Peeper's direct involvement in these events is limited, his scientific background and household remain integral to the season's adventures.