captions) and introductions written by the four authors. They also wrote a bi-annual lookback on the major developments in the UK charts in the two preceding years. The series was soon regarded as the number one source for music and chart reference, thanks to the commercial success of the books and its various sister publications (see below). The series' 10th edition, published in June 1995, was the last to feature its original authors Rice, Rice and Gambaccini. From the 11th edition onwards, the book was compiled by in-house editors at Guinness Publishing and, later, by David Roberts who had already been a chart editor and designer for the original team. 1997–2006 From the 12th edition onwards (published in 1999), the book was published every year rather than bi-annually. In 2004, the book merged with The Guinness Book of British Hit Albums to form The Guinness Book of British Hit Singles & Albums. The eighteenth edition of the book (2005) was billed as a "Special Collector's Edition" as it featured detailed information on the 1,000 Number Ones in the UK Singles Chart from Al Martino's "Here in My Heart" on 14 November 1952 to Elvis Presley's "One Night / I Got Stung" (Limited Edition Collector's re-issue), 22 January 2005. The 19th edition (2006) was the last in the series. A supposed 20th edition was due to be published in 2007, but apparently the original publishers lost interest in chart reference books after their contract with The Official Charts Company expired, which saw that organisation sell the contract to Virgin. Features in each edition Associated merchandise Following the success of the Guinness Book of British Hit Singles series, the original authors and Guinness quickly turned to other charts-related books and projects. The following books were written by them: The Guinness Book of Hits of the 70s (1980) The Guinness Book of 500 Number One Hits (1982) The Guinness Book of British Hit Albums (first issued in 1983, second edition in 1986 with bi-annual updates until 1996) The Guinness Book of Hits of the 60s (1984) The Guinness Hits Challenge (a pop quiz book) (1984) The Guinness Hits Challenge 2 (1985) The Guinness Book of Number One Hits (2nd edition) (1988) UK Top 1000 Singles (1988) Hits of the 80s (1990) The Guinness Hits Quiz (1990) Guinness Top 40 Charts (1992) The Guinness Hits Quiz 2 (1992) UK Top 1000 Singles 2 (1993)