Green Jacket by Jennette Lee

An early example of the female private detective, Jennette Lee’s Millicent Newberry made her first appearance in The Green Jacket in 1917 and was also featured in two later books, The Mysterious Office in 1922 and Dead Right in 1925. Miss Newberry brings her own unique perspective to her cases, only accepting those where she has a say in what happens to the guilty party. She is rarely without her knitting, using it as a technique to put clients and suspects alike at ease, while also knitting her notes on the case into the pattern! In The Green Jacket, Millie goes undercover to solve a case involving a stolen emerald necklace that, despite the efforts of other detectives, including her former boss, Tom Corbett, has never been recovered.