The scientific study of hobos.
"These two were dipping lettuce into coke, then licking and sucking on the lettuce. When I walked by them they appeared to be engaged in deep conversation, speaking in their own hobotastic dialect. I didn't want to distrub this facinating exchange, and so I decided to take a picture from a distance instead of approaching. This is often my method of study, because it is hard to properly photograph a hobo once it knows that you have entered it's hobotat. They become quite edgy and often attack verbally."