Start with high-confidence portrait photography books, then narrow by subgenre or adjacent topics.
Vivian Maier
John Maloof
Body
Nathalie Herschdorfer
Arcadia Britannica
Henry Bourne
Face to Face
Camilla McGrath, Andrea Di Robilant
Ryan Mcginley: Yearbook
Ryan McGinley
Iphone Photography for Dummies
Mark Hemmings
Humans
Brandon Stanton
Dear New York
Vanity Fair: Oscar Night Sessions
Mark Seliger, Alan Cumming
Animal Kingdom
Randal Ford, Dan Winters
Haunted Air
Ossian Brown
Frank S. Matsura
Michael Holloman
Blind Corners
Michael Collins, Will Self
Portrait of an Artist
Hugo Huerta Marin
Andy Warhol. Polaroids 1958–1987
Richard B. Woodward, Reuel Golden
Surf Tribe
Stephan Vanfleteren