Thomas Lord Busby's 1820 volume Costume Of The Lower Orders was part of a genre of books that featured colourful paintings depicting working people in the streets of London, generally viewed through the lens of an aristocratic voyeur. They're a kind of visual companion to Mayhew's classic London Labour and the London Poor (though this latter dates 20 years after Busby's book).
Another important volume is Thomas Rowlandson's Characteristic Series of the Lower Orders, which Spitalfields Life has excerpted in two posts (1, 2).
Spitalfields Life has lots more like this: see, for instance, the more staid illustrations in Richard Dightons City Characters (1824); and Marcellus Laroon's Cries of London (which was in print from 1687-1821).
