Paine was political pamphleteer, originally from England. His book "Common Sense" was an argument for American Independence - and became one of the most popular books in American history, mainly because Americans thought it was a book about common sense, and on some level knew they needed it. While the book wasn't what convinced Congress of the value of independence (they already knew), it did cause a groundswell of popular support, and that was important because Congress needed the public on their side - and they needed to convince soldiers to fight for them. Common Sense did both.