Inverness author Elisabeth Ptak wears more than one journalistic hat: she’s written several books, on-air essays for KWMR and KQED and columns for the Light, and she was a contributor to the West Marin Review. Her newest book is a biography—or maybe it’s better called a “duography.” It’s also a picture book and a slice of gay history. Her main subject, Sydney Engelberg, who lived from 1912 to 1997, shares the book’s spotlight…