I really dont think enough attention is paid by contemporary Chestertonians to the contributions that GKC made to the genre of detective fiction. The Illustrated London News essays contain several gems of insight into AC Doyle, Holmes, and the modern detective novel itself.
One of the first books I ever bought as a kid, which I still own, was a collection of facsimilie reprints of the original Sherlock Holmes stories from The Strand. I can still remember picking that book up and paging through those wonderful Sidney Paget illustrations, knowing that I had indeed found something special. I still pick up Holmes pastiches here and there, Larry Millet writes some excellent ones, placing Sherlock Holmes in turn of the century Mpls-St. Paul. Ive bought a couple of Sherlockian collections/criticisms which include reprints of some of the GKC essays, or at least make reference to GKC as a literary figure of the time
There are a couple points I believe we should keep in mind from this. First, Chesterton is not "just" an essayist and journalist, but is a figure of great stature in mystery and detective fiction. A great deal of Chesterton's appeal to me is that as a man of deep faith and conviction, he was also a fabulous writer discussed in the same circles as AC Doyle and Agatha Christie. I think Chesterton is an example par excellance of what a believer in the world should be. Instead of writing saccharine literature, or Left Behind types of Christian pulp, Chesterton's fiction writing wasnt Catholic literature.........but solid, high quality literature written by a Catholic.
Second, even in his day, Chesterton paid the price for his conversion. I never heard of Chesterton in school, yet I now realize that one really cannot properly study Sherlock Holmes, George Bernard Shaw, or even modern English literature without him. Chesterton's career and legacy suffered due to his conversion. Going back over these books now is incredible. As a lifelong Sherlock Holmes fan, I have to say that knowledge of Chesterton is elementary to understanding the Holmsian canon.