According to Official Guinness Records,
The thickest published book measures 322 mm (12.67 in) in width and was unveiled by HarperCollins in London, UK, on 20 May 2009. All Agatha Christie's Miss Marple stories - 12 novels and 20 short stories - are collected and published in this volume. The book contains 4,032 pages and weighs 8.04 kg. There are 68 crimes committed;11 philandering lovers;68 secrets and lies;22 false accusations;59 red-herrings and 21 romances. In all, 43 murders are solved: 12 poisonings;6 strangulations;2 drownings;2 stabbings;a burning;one blow to the head;one death by an arrow and 2 people pushed. 143 cups of tea are drunk in the massive volume, there are 66 maids and 47 garments are knitted. 500 copies of this limited edition record-breaking book will be produced and they will retail at £1,000 each.
For a complete list of 2009 records, please visit 2009 Guinness Records in United Kingdom.