Economics is an introductory textbook by American economists Paul Samuelson and William Nordhaus. The textbook was first published in 1948, and has appeared in nineteen different editions, the most recent in 2009. It was the best selling economics textbook for many decades and still remains popular, selling over 300,000 copies of each edition from 1961 through 1976. The book has been translated into forty-one languages and in total has sold over four million copies.