Okay people just have a quick question about the greatest detective… so if detective comics is batman what is the difference between Batman’s own series and his detective series
The distinction is mainly an artifact of the early years, when Detective Comics was an anthology of multiple characters and the Batman title was all-Batman.
Detective Comics has occasionally gone back to anthology format or followed different characters, but usually the only difference is they have separate writers and artists working on them.
The answer to that question differs depending on the era. Detective Comics was originally an anthology series featuring many characters. Eventually, Batman became the featured character for every issue, but other characters would still get their own stories after the Batman story. For instance, the 1960s issues of Detective Comics tended to include Elongated Man stories, and the early 1980s issues included Green Arrow stories.
The comic entitled Batman, on the other hand, was designed for the sole purpose of printing Batman stories. Some of the stories might feature a member of Batman’s supporting cast (Robin, Alfred, and so on), but it was very much a book about Batman and not a book about detectives in general.
Starting in 1987, the books became interchangeable. They were both pretty much exclusively Batman books. Every once in a while, DC will do something different with Detective Comics, but it’s usually just another Batman book.