This is a fixed-episode-count podcast (they just put out the final episode) about John Coltrane and his music and his impact on jazz.
Most episodes are pretty short (~10 mins) and involve either interviews/commentary with experts on John Coltrane (or the quartet) or with people who played with him, such as McCoy Tyner, Jimmy Cobb, Charles Tolliver, Steve Kuhn.
A few episodes dive pretty deeply into the kinds of music things that Coltrane did that were so revolutionary. I found every episode to be extremely fascinating (and educational!).