Dorothy Dunnett 
Roman Nights [PDF ebook] 
Dolly and the Starry Bird ; Murder In Focus

Ruth Russell, an astronomer working at the Maurice Frazer Observatory, is enjoying herself in Rome — that is, until her lover, Charles Digham, a fashion photographer and writer of obituary verses, has his camera stolen. The thief ends up as a headless corpse in the zoo park tolleta. Johnson Johnson, enigmatic portrait painter, spy and sleuth, is in Rome to paint a portrait of the Pope and is therefore on hand to investigate in one of Dunnett’s usual thrilling and convoluted plots that grips the reader from cover to cover. There is something far more deadly at stake than just the secrets of a couture house …