The app Truecaller estimates that as many as 56 million Americans have fallen foul to scam calls, losing nearly $20 billion. Enter L., an anonymous vigilante, referred to here by his middle initial, who seeks to expose and disrupt these scams, posting his work to a YouTube channel under the name “Jim Browning.” On today’s Sunday Read, Yudhijit Bhattacharjee follows L.’s work and travels to India to understand the people and the forces behind these scams.