Ronald Perelman is the archetypal modern tycoon. The cigar-chomping, 70-year-old businessman is bald, virile, contentious and ridiculously wealthy. Mr. Perelman built his reputation as a leading investor and a corporate raider of big companies in the ’80s. In 1985, he took over Revlon for $1.8 billion in junk bonds—one of the defining events of the decade. Mr. Perelman has since amassed a fortune estimated by Forbes at $12 billion. And although his company, MacAndrews & Forbes, still maintains extensive holdings, its role in shaking up corporate America has probably crested. Mr. Perelman now devotes himself to giving away his billions with the same ambition and zest with which he earned them. He is one of New York City’s most generous philanthropists. His hundreds of donations include the following: $20 million to Carnegie Hall, $20 million to the Guggenheim Museum, $50 million to the New York Presbyterian Hospital & Weill Medical College of Cornell, and $10 million to New York University.