Jack Paar was an American entertainer and television host best known for his stint as the host of The Tonight Show from 1957 to 1962. He was known for his wit and humor, which often included political satire and social commentary. He was also known for his frequent use of the phrase 'I kid you not' during his monologues. Paar was a pioneer in late-night television, paving the way for future hosts such as Johnny Carson and Jay Leno.