The product is a set of four complete novels by Trevanian, including "The Eiger Sanction," "The Main," "Shibumi," and "Loo Sanction." Published in 1981 by Avenel Books, these hardcover novels are all in English language. The collection offers readers a selection of thrilling and espionage-filled narratives crafted by the talented author, making it a must-have for fans of Trevanian's work.