It is another sunny morning in west Los Angeles, and Mel Bouzad has set his goal for the day: he wants to get pictures of Jennifer Lopez and Jennifer Garner—"you know, Ben's girls," he says with a laugh. As one of L.A.'s top paparazzi, Bouzad, 26, makes it his business to know where celebrities will be at any given time. He has decided to check on a gym where Garner works out in the mornings. He makes a U-turn in his silver Mercedes CLR convertible while talking on a cell phone in his thick Cockney accent to his office about a billing problem: "Tell them we need more money. We can blacklist the magazine. We don't need them. They need us."

The question of who needs whom is a pointed one. Most stars accuse the paparazzi of being bottom-feeders who profit from stalking and harassment. The photographers, however, maintain that these same celebrities secretly know they can't do without paparazzi. "Celebrities need a higher level of exposure than the rest of us," says Peter Howe, author of Paparazzi, which chronicles the history of the trade. "So it is a two-way street. The celebrities manipulate the paparazzi too." And the money is huge. "If I get Britney and her baby, I'll be able to buy a house in those hills," says Bouzad, pointing to the mansion-studded slopes above Sunset Boulevard. "That would go for $2 million worldwide."

Bouzad's biggest single sale has been a picture of Ben Affleck and Lopez in Georgia after their breakup, for which he claims to have earned $150,000. "I got a tip from Matt Damon's girlfriend's hairdresser," he says. Like all other successful paparazzi, Bouzad has a network of bodyguards, barmen, waiters and concierges whom he pays for tips.

Bouzad was born in London and began freelancing at 17. His first picture sale was of Liam Gallagher from the band Oasis. Bored during a long stakeout at Gallagher's home, Bouzad ordered a pizza to the house and shot Gallagher as he answered the door. Bouzad arrived in Los Angeles 31/2 years ago with a camera bag and a suitcase of clothes. Now he runs his own company, MB Pictures, and employs seven other photographers.

Bouzad cruises along Sunset Boulevard, where he spots two paparazzi parked outside the Chateau Marmont hotel. "They are waiting for Cameron Diaz—facing both directions so they don't have to make a U-turn on Sunset," he says. Then he drives into the Hollywood Hills and reels off the names of stars as he passes their houses: Halle Berry, Keanu Reeves, Tobey Maguire, Courteney Cox.

By midafternoon, when Bouzad decides to head home, he has no pictures—but he doesn't feel down. The public needs him. The magazines need him. Even the celebrities need him. And he knows that every day he has the chance to make more money with one picture than most people—except maybe movie stars—earn in a year.