William Schwartz, like many of the post muralists, was an immigrant. During his life, he worked as a house painter, newspaper salesperson, waiter, theater usher, opera singer, radio performer, and, of course, artist. How one has time for so many talents is beyond me. You can see examples of his work at Modernism in the New City, Incollect, and the Art institute of Chicago.
Schwartz made three post office murals: Mining in Illinois (Eldorado, Illinois), Old Settlers (Fairfield, Illinois), and Riverboat and Bridge (Pittsfield, Illinois).