What the city directories can tell you

I’m still working on the 1900 census, so I really have no business looking at any other year until 1900 is done. But I did look at another year and this is a good project to pursue, for someone else, so feel free to steal this idea. The last census available to me is 1930. So, I’m going to have to wait a couple of years before the National Archives releases the 1940 census, but there is a way to find out who lived in the hood between 1930 and 1970, the city directories.
In the back of the city directories, there are names and businesses listed by address. So out of curiosity I picked the 1400 block of North Capitol. I was randomly looking at years and addresses but probably with the 1940 City Directory there is Catania Bakery, a grill, and another restaurant on North Cap. Actually several businesses. Got me to wondering what did the commerical corridor of North Capitol look like, pre-war, pre-riots.