American lyricist Sam M. Lewis (1885–1959) was a prolific contributor to early 20th-century popular music, penning lyrics for over 2000 songs. He is best known for his collaborations with Joe Young and Fred E. Ahlert, creating numerous Tin Pan Alley hits that became jazz standards. His enduring compositions include "When You're Smiling (The Whole World Smiles With You)" and "I'm Sitting on Top of the World."