The Call of Cthulhu monograph series varies tremendously in quality, and Casting Call of Cthulhu is one of the best. It contains dozens of NPCs for use in modern-day Call of Cthulhu games as people who might be informants or provide specialized assistance to the investigators.
A key element of why the Casting Call of Cthulhu is so effective is its organization. The NPCs are listed by the "field" they are in - art, crime, law enforcement, media - meaning that when the players suddenly, out of nowhere, want to go to the press (for example), you have several to choose from. The characters presented are diverse, and each are given fully humanizing qualities - you never know what characters the players will seize on as appealing, so having a solid background, goal, and personality helps bring them quickly to life.
Call of Cthulhu isn't a game that lives or dies by its recurring NPCs - this is a tremendous first step towards filling out a setting that can otherwise feel empty and isolating as the horror genre tends to be.
The missteps in the piece involve some typos (a problem throughout the monographs) and some archaic terms that don't reflect how best to describe a diverse set of peoples. (C'mon, "Oriental"? I get that Gary Gygax used it but Said published Orientalism in 1978. Can't we have caught up by now?)