The author has delved into the archives in Cambridge, producing a complete record of the music that has been used in the Festival of Nine Lessons and Carols at King's over the last 100 years. This book reveals the most performed carol from the Festivals since the first one in 1918. It also has some comments made by Sir David Willcocks, giving his ideas for adapting the service. The book mentions the scheme, devised by Boris Ord, for performing the opening hymn, Once in royal David's city, and identifies the keys that he used for certain carols. It reminds readers of the modern composers that Sir Philip Ledger introduced into the Festivals, as well as highlighting popular carols from Sir Stephen Cleobury's era.