This Boy by The Beatles is a heartfelt ballad about the pain and longing associated with unrequited love. Paul McCartney and John Lennon harmonize to express the deep sorrow felt by a boy who has lost his love to another. Key themes include heartbreak, hope, and yearning. Particularly poignant moments in the song include the emotional chorus where the boy laments his loss and expresses his wish for his love to return. This Beatles classic is a testament to the timeless struggle of love and loss.