I wasn't really scared as I walked north along Cottage Grove Avenue. A little nervous, certainly, but I was pretty sure that J.T. didn't see me as any kind of threat. Worst-case scenario? Embarrassment. He and his gang would ask me to leave or they'd laugh at my desire to get to know them better.

It was maybe two o'clock in the afternoon when I arrived. This time I came bearing a six-pack of beer. There were about a dozen young men in front of No4040, standing around their cars. Some of them began to point at me. A few others were playing handball by throwing a tennis ball against the building. As I drew close, all turned to watch me.

“You've got to be kidding me,” I heard someone say. Then I saw J.T. smiling and shaking his head.

“Beer?” I said, tossing him a bottle. “You said I should hang out with folks if I want to know what their life was like.”

J.T. didn't answer. A few of the guys burst out laughing in disbelief. “He's crazy, I told you!” said one.

“Nigger thinks he's going to hang out with us!”

“I still think he's a Latin King.”

Finally J.T. spoke up. “All right, the brother wants to hang out,” he said, unfazed. “Let him hang out!”

J.T. grinned and opened up his bottle. Others quickly grabbed the rest of the beers. Then they all went back to their business. They didn't seem to be discussing anything very pressing, nor were they talking about any criminal activities. They mainly talked about what kind of rims to put on their cars. A few took care of the drug customers, handing vials of crack to the people who walked over from nearby buildings or drove up... A handful of gang members stood guard in front of No4040, and after a time some of the guys hanging out near the cars relieved them.

Gang Leader for a Day, by Sudhir Venkatesh
Allen Lane, £18.99

Times Recommends

• The 100 Best Books of the Decade
• The Times picks the 50 best paperbacks of 2009
• The conversation: James Ellroy