(written from a Production point of view)
Cosmo Genovese was the script supervisor for Star Trek: The Next Generation and the first six seasons of Star Trek: Voyager. He was also script supervisor for the Star Trek: Deep Space Nine episode "The Jem'Hadar" and the video games Star Trek: Borg and Star Trek: Klingon.
A few joke references to Genovese appear throughout TNG and Voyager: a Lieutenant Cosmo Genovese is seen on various dedication plaques and directories; Genovese's Star is listed on a tactical situation monitor seen in TNG: "Yesterday's Enterprise"; a flower shop called Genovese's Flowers makes an appearance in the TNG episode "Manhunt"; and Bio-genovesium appears in TNG: "Night Terrors".
Before Star Trek, Genovese was the script supervisor for the original Perry Mason television series from 1957 through 1963. He went on to become script supervisor for the 1980s adventure series The A-Team, starring recurring TNG performer Dwight Schultz. He was also a script supervisor on HBO's Tales from the Crypt and the 1995 film Tales from the Crypt Presents: Demon Knight, starring William Sadler, John Schuck, Dick Miller, and Tim de Zarn and featuring the voice of John Kassir.