In 1995, Drew Dixon was working her dream job as an executive at Def Jam Recordings, helping to oversee a chart-topping album and a ubiquitous single by Method Man and Mary J. Blige. But as her star rose, Ms. Dixon, then 24, was spiraling into depression, she said, because of prolonged and aggressive sexual harassment by her direct supervisor, Russell Simmons, the rap mogul and co-founder of the label. On work calls, he would talk graphically about how she aroused him. At a staff meeting, he asked her to sit on his lap. He regularly exposed his erect penis to...