Arnold Hylen (1908-1987) was a commercial and architectural photographer based in Los Angeles. Between the late 1940s and the late 1960s, Hylen traversed the streets of Los Angeles, photographing its vanishing landscape. He contributed photographs to St. Vibiana's: Los Angeles Cathedral (1950) and produced a slim folio The Vanishing Face of Los Angeles (1968). His two books are Bunker Hill: A Los Angeles Landmark (1976) and Los Angeles Before the Freeways (1981).

Nathan Marsak studied under the eminent historian of Los Angeles, Reyner Banham, at University of California, Santa Cruz, and completed his graduate work with noted Sullivan/Wright scholar Narciso Menocal at University of Wisconsin, Madison. He worked on the curatorial staff of Los Angeles Museum of Contemporary Art and served as historian for the LAPD Museum archives. He is also the author of Bunker Hill Los Angeles and Los Angeles Neon. He lives in Los Angeles.