As a reaction to the closure of libraries during the COVID-19 pandemic, I've been re-reading some of my extensive collection of classic detective stories, collected over most of my adult life. Specifically, I've been re-reading Ellery Queen novels, which I've read off and on for most of my adult life. In recent years I've been exploring new mystery writers at the local library, but that stopped with the shutdown, so I returned to what I had.
The Ellery Queen novels debuted in 1929 with The Roman Hat Mystery and continued into the early 1960s, after which the authors, Frederick Dannay and Manfred B. Lee, also allowed other writers to create Ellery Queen novels which didn't feature their detective, Ellery Queen, as a character. Most of the novels and stories I've been reading were written in the 1930s.
Given the Black Lives Matter protests over the last few weeks, I'm unusually sensitive to racism. I didn't think of Ellery Queen novels as racist, but I notice that while the Ellery Queen character almost never uses racial slurs, the New York City cops who feature in many stories do. This includes the character Inspector Richard Queen, Ellery's father. I especially noticed the use of the phrase "the shine" to refer to what a more educated person would probably have called "the Negro." This was well before the use of phrases like black, African American, or people of color. I also noticed that even when not using racist slang, descriptions of Negro characters, such as hotel maids, were condescending at best.
You can't go back and change history, or classic novels. In fact I've seen much worse racism in "tough guy" detective novels by Raymond Chandler and Mickey Spillane. I think the explanation has to be that some people in the 1930s talked that way, and the authors put it in for realistic effects. I still think the Ellery Queen novels are worth reading for the amazing logical puzzles they present. I've always preferred puzzle mysteries to the shoot-em-up types.