Complex sentence: The first edition was published as the The Guinness Book of British Hit Singles in July 1977 and this title was merged with its sister-publication The Guinness Book of British Hit Albums in 2004 to form its current branding.
Split into simpler sentences: The first edition was published as the "The Guinness Book of British Hit Singles" in July 1977. This title was merged with its sister-publication "The Guinness Book of British Hit Albums" in 2004 to form its current branding.