Alyssa Monas sits before a half-dozen toddlers, clutching a steady old friend, the $150 acoustic guitar her mother bought for her on a cable shopping network ages ago. “Good morning, friends,” Monas ...

Paul McCartney wrote “Hello, Goodbye” in 1967. The song became a non-album single and has endured as one of their better-known hits. At this stage in The Beatles’ career, McCartney and John Lennon ...