Great Scott...600 episodes?! To mark the occasion, I'm on a trip to 221B Baker Street with my favorite radio adventures of Sherlock Holmes. In this super-sized Sherlock special, we'll hear John Gielgud and Ralph Richardson in "A Scandal in Bohemia." Basil Rathbone and Nigel Bruce are Holmes and Watson in "The Notorious Canary Trainer" (originally aired on Mutual on April 23, 1945) and "The Speckled Band" (originally aired on Mutual on November 12, 1945), and then Bruce is joined by Tom Conway as Holmes in "The Adventure of the Tolling Bell" (originally aired on ABC on April 7, 1947). My personal favorite Holmes and Watson - John Stanley and Alfred Shirley - headline "The Laughing Lemur of Hightower Heath" (originally aired on Mutual on October 26, 1947), "The Cadaver in the Roman Toga" (originally aired on Mutual on November 9, 1947), "The Stolen Naval Treaty" (originally aired on Mutual on November 23, 1947), and "The Case of the Sudden Senility" (originally aired on Mutual on January 11, 1948). And finally, it's - appropriately enough - "The Final Problem," with Gielgud, Richardson, and special guest star Orson Welles as Professor Moriarty.

In the mood for more Holmes and Watson?

Click here for our spotlight show on Edith Meiser, the woman who brought Holmes to radio and penned his adventures for years.

And here's a collection of mysteries featuring Holmes and Watson battling seemingly supernatural foes.