When Robert Preston shouted "Ya got trouble " in River City, when Carol Channing glided down a gilded staircase while waiters serenaded her with "Hello, Dolly ," when Barbra Streisand defied us to rain on her parade in Funny Girl, audiences were instantly enchanted. Showstoppers is all about Broadway musicals' most memorable numbers--why they were so effective, how they were created, and why they still resonate. Much of it is told through the eyes...