The singing of carols was further popularised in the 20th century when OUP published one of the most popular carol books in the English-speaking world, "Carols for Choirs". First published in 1961 and edited by David Willcocks and Reginald Jacques, this bestselling series has since expanded to a five-volume set. Along with editor John Rutter, the compilers included many arrangements of carols derived from sources such as Piae Cantiones, as well as pieces by modern composers such as William Walton, Benjamin Britten, Richard Rodney Bennett, William Mathias and John Rutter.