Longstreet was based in part on characters created by Baynard Kendrick. Kendrick was the author of a series of detective novels published from the late 1930s through the early 1960s featuring a blind private detective named Duncan Maclain. While all Kendrick's Maclain books are now out of print, you can locate them in used book stores, online used book sellers (such as Alibris), and even on eBay. To aid you in your quest, here is a list of the Maclain stories compiled by Kevin at the Thrilling Detective web site.
NOVELS
The Last Express (1937) The Whistling Hangman (1937) Odor of Violets (1941; AKA Eyes in the Night) Blind Man's Bluff (1943) Death Knell (1945) Out of Control (1945) You Diet Today (1952; AKA You Die Today) Blind Allies (1954) Reservations for Death (1957) Clear and Present Danger (1958) (more of a spy novel than a murder mystery) The Aluminum Turtle (1960; AKA The Spear Gun Murders) Frankincense and Murder (1961)
SHORT STORIES
"The Murderer Who Wanted More" (January 1944, The American Magazine; also issued as a special 10-cent Dell paperback in 1951) "Melody of Death" (June 1945, The American Magazine) "Silent Night" (1958; also 1982, Murder For Christmas, Volume 2) "The Silent Whistle"
COLLECTIONS
Make Mine Maclain (1947 - three novelettes)
Another great book by Baynard Kendrick to look out for is Lights Out (1945). It's not a Maclain novel or a detective story at all. It is the story of an army sergeant blinded in World War II. The novel takes you through the army's rehabilitation process and also follows the protagonist as he learns to deal with his blindness. As he builds a new life, he confronts love, security, racism, and independence. It is a very powerful story and worth seeking out. This novel was made into a movie, Bright Victory (1951), which garnered an Oscar nomination for best acting for Arthur Kennedy. It has not been released on pro video, but seek it out on classic movie stations or see the Collector Info page for tape trading info.
You can read more about Kendrick from a blurb on the cover of one edition of Lights Out.
More Kendrick links to explore:
Here are just a few samples of covers from some of Baynard Kendrick's Maclain books. These editions were reprinted during the early 1970s and mention the connection to the TV series Longstreet.