Dario Argento (b. 1940) started as a film critic and screenwriter — he co-wrote the story for Sergio Leone's Once Upon a Time in the West — before turning director with The Bird with the Crystal Plumage (1970), a giallo thriller that became an immediate international hit and helped shape the genre's visual grammar: black-gloved killers, elaborate murder set pieces, and camera work that implicates the viewer as a voyeur.
Argento's peak run through the 1970s and early '80s — Deep Red, Suspiria, Inferno, Tenebre — pushed giallo toward something closer to horror opera, pairing baroque violence with progressive rock scores (many by the band Goblin) and production design that focused on mood and color over realism. Suspiria in particular, with its saturated primary-color lighting and dance-academy-as-haunted-house premise, has become one of the most visually influential horror films ever made, still referenced constantly in cinematography and fashion decades later.
Argento's later career has been more uneven, but his influence on horror aesthetics — internationally, not just within Italian genre cinema — is difficult to overstate. Collectors drawn to giallo, or to horror as a visual medium rather than a purely narrative one, will find Argento's catalog to be essential, era-defining material.