Sergio Toppi was an Italian illustrator and comics author from Milan. Toppi's art style is known for its sophisticated compositions and an unmatched ability with hatching. Young Toppi left his medical studies in the early 50's to pursue a career in illustration, which lasted until his death at age eighty. His illustrations were featured in many Italian newspapers, magazines and books. Toppi also developed a comics career since the middle of the 60's. His body of work in comics is mostly composed of short stories on a wide range of subject matters, often in a historical or fantasy setting. Toppi's stories appeared in a number of Italian comics magazines, from the ones devoted to kids such as Il Corriere dei Piccoli and Il Giornalino, to those targeting a more mature or larger audience, like Sgt. Kirk, Linus, alter alter, Corto Maltese, L'Eternauta, Comic Art, Orient Express. For the latter magazine Toppi created in the 80's his only recurring comics character, called Il Collezionista (The Collector).

Alfredo Castelli began his comic book career at an early age, creating the strip Scheletrino, a humor series for Italian comic book Diabolik, when he was only 16 years old. In 1967 he began writing scripts for several Italian comic magazines, including Pedrito el Drito and Piccola Eva, Cucciolo, Tiramolla and Topolino. In 1969 he contributed to the humor magazine Tilt. A year later, together with Pier Carpi, Castelli created Horror magazine, in which he published his strip Zio Boris. He then joined the staff of Il Corriere dei Ragazzi as editor/artist/writer. For this magazine he created L'Ombra, a personal take on The Invisible Man drawn by Ferdinando Tacconi; Gli Aristocratici, a group of gentlemen thieves, again with art by Tacconi; Otto Kruntz, a mad scientist drawn by Daniele Faragazzi; and L'Omino Bufo, an absurdist humor illustrated by Castelli himself. In 1978 Castelli wrote for Supergulp magazine the adventures of Allan Quatermain, an explorer specializing in archaeological mysteries that foreshadowed Castelli's most famous creation. In the same year Castelli began his cooperation with publisher Sergio Bonelli, writing stories for Zagor and Mister No. In 1982 he created Martin Mystère. The series, initially drawn by Giancarlo Alessandrini, marked a turning point in Italian popular comics history, introducing modern and sophisticated themes in a market dominated by traditional adventures aimed at a younger audience. In 1992 Castelli launched the new series Zona X, a spin-off of Martin Mystère, that ran until 1999.