The Vanguard is the fourth adventure sourcebook in the Chi-Town 'Burbs series.
https://palladium-store.com/1001/product/856-Rifts-Adventure-Sourcebook-Four-The-Vanguard.html
Official summary[]
Rifts® Adventure Sourcebook Four: The Vanguard™ The Vanguard. Born in the days before Chi-Town forever banned the used of magic on Coalition soil, these practitioners of magic fight for the Coalition States and the Prosek regime. They do so in secret, quietly undermining agents of the Federation of Magic and other CS hate groups. Learn about their organization, goals, current operations and how they continue to serve the CS, even though they are hunted as dangerous fugitives by the very nation they work to protect. Cat No. 856 Page Count: 48 pages. Cover by: Freddie Williams. Interior Art: Perez, Williams, Okamura and others. Writen by: Kevin Siembieda.