Do you have family living in the Los Angeles, California area between the late 19th century and mid-20th century? If you do, the Los Angeles Public Library has a terrific resource available online – a collection of digitized city directories.
Yes, Ancestry has a collection, but some years are missing (as are some in LAPL’s collection) and some directories seem to have only parts of them available digitally.
Between the two resources, you have an excellent chance of finding a directory in the time frame in which your family lived there.
The LAPL collection is free and, while it isn’t complete, it does have a bonus – there are directories online for nearby towns like Westwood, Santa Monica, the San Fernando Valley and Van Nuys.
Los Angeles Public Library City Directories Online
Other directories include the 1930-1931 Los Angeles Negro Directory and Who’s Who:
There are separate business directories for some years:
California isn’t always the easiest place to find records, given the population and some non-existent vital records so city directories are a way to supplement sometimes meager family information.
I didn’t find many digital collections online at the Los Angeles Public Library, aside from some photo collections, but I think city directories are the most useful of what is currently available.