The HBO crime drama "The Wire" is universally acclaimed for its realistic depiction of several aspects of a modern American city, most prominently the drug trade. By watching "The Wire," you can get a workable idea of how the drug trade works. Here are four episodes of "The Wire" that show a particular focus on the specifics of the drug trade.

"The Target." The pilot episode of "The Wire" provides the viewer with a handy introduction to the drug distribution engine in Baltimore. Specifically, you can get a vivid sense of the brutality and ruthlessness that goes into the business of illicit drugs, as the episode ends (and the entire first season revolves) around the murder of a man who testified in court against D'Angelo Barksdale, who works for his uncle Avon, the most feared drug lord in Baltimore.

"The Wire." Here's another first season episode that shows some of the street-level aspects of the drug trade. As if you didn't already know, brutality is still the name of the game. In this episode an associate of the legendary stick-up man Omar Little is brutally tortured and killed, with his eyes being burned out for good measure. Viewers also spend some time with Bubbles, a homeless drug addict who exists at the bottom rung of Baltimore society.

"Cleaning Up." In the penultimate episode of season one of "The Wire," one of the most memorable and terrifying examples of the Barksdale association's ruthlessness can be unflinchingly seen. A 16-year-old low-level operator by the name of Wallace is deemed a threat to the organization by Avon's cold, business-oriented second-in-command, Stringer Bell. So he assigns two of Wallace's friends, Poot and Bodie, to take him out. His death scene is harrowing, terrifying, and unforgettable. The lesson here is that in an environment like Baltimore, dead bodies are an unavoidable result of the drug trade.

"Final Grades." The fourth season finale of "The Wire" is often considered the best episode of the entire series. The fourth season follows a group of young and innocent youths who except being born in the wrong place at the wrong time, and eventually get caught up in the city's drug trade. Arguably the most tragic example is Michael, who goes from being a promising young man to a puppet of Marlo Stanfield, a drug lord who makes Avon Barksdale look like an Avon lady.

In order to really grasp the mechanics of the drug trade depicted in "The Wire," you really have to watch the entire series. Especially if you're interested in all of the subtle nuances of character and plot. But, in the meantime, these four episodes should teach you a little bit about the drug trade.