<b>The Big Four </b>is a work of detective fiction by <b>Agatha Christie</b>, first published in the UK by William Collins &amp; Sons on 27 January 1927 and in the US by Dodd, Mead and Company later in the same year. It features <b>Hercule Poirot</b>, <b>Arthur Hastings</b>, and <b>Inspector Japp</b>.&nbsp;<br /><br /><b>Dame Agatha Mary Clarissa Christie</b>, <b>Lady Mallowan</b>, (n&eacute;e Miller; 15 September 1890 &ndash; 12 January 1976) was an English writer known for her <b>66 detective novels</b> and <b>14 short story collections</b>, particularly those revolving around fictional detectives <b>Hercule Poirot</b> and <b>Miss Marple</b>. She also wrote the world&#39;s longest-running play, the murder mystery <b>The Mousetrap</b>, which has been performed in the West End since 1952. A writer during the &quot;Golden Age of Detective Fiction&quot;, Christie has been called the &quot;<b>Queen of Crime</b>&quot;. She also wrote six novels under the pseudonym Mary Westmacott. In 1971, she was made a Dame (DBE) by <b>Queen Elizabeth II </b>for her contributions to literature. Guinness World Records lists Christie as the best-selling fiction writer of all time, her novels having sold more than two billion copies.