Mark Lewisohn (born 16 June 1958) is an English author and historian, regarded as the world's leading authority on the English rock band The Beatles.

Over the course of his career, Mark Lewisohn has worked for EMI, MPL Communications and Apple, and has written many reference books about The Beatles. He has been referred to as the world's leading authority on the subject, renowned for his meticulous research and integrity. He is credited with discovering such facts as the precise date when John Lennon first met Paul McCartney.

In 1986, Lewisohn's book The Beatles Live! was published. This featured a complete history of all the Beatles' live performances, in a format which Lewisohn would follow for his subsequent books. After being invited by EMI to listen to all of The Beatles' original session tapes, Lewisohn wrote The Complete Beatles Recording Sessions: The Official Story of the Abbey Road Years, which was published in 1987. The book was in the form of a diary, detailing every recording session The Beatles had at Abbey Road Studios chronologically. It included details such as who played on each track and how many takes were recorded in each session. The book featured an introductory interview by Paul McCartney.

Adam Smith (baptised 16 June 1723 – 17 July 1790 [OS: 5 June 1723 – 17 July 1790]) was a Scottish social philosopher and a pioneer of political economy. One of the key figures of the Scottish Enlightenment, Smith is the author of The Principles Which Lead and Direct Philosophical Enquiries, Illustrated by the History of Astronomy, prior to 1758, The Theory of Moral Sentiments, 1759, and An Inquiry into the Nature and Causes of the Wealth of Nations, 1776. The latter, usually abbreviated as The Wealth of Nations, is considered his magnum opus and the first modern work of economics. It earned him an enormous reputation and would become one of the most influential works ever published. Smith is widely cited as the father of modern economics and capitalism and is still among the most influential thinkers in the field of economics today. In 2009, Smith was named among the 'Greatest Scots' of all time, in a vote run by Scottish television channel STV.

Smith studied social philosophy at the University of Glasgow and at Balliol College in the University of Oxford, where he was one of the first students to benefit from scholarships set up by his fellow Glaswegian John Snell. After graduating, he delivered a successful series of public lectures at Edinburgh, leading him to collaborate with David Hume during the Scottish Enlightenment. Smith obtained a professorship at Glasgow teaching moral philosophy, and during this time he wrote and published The Theory of Moral Sentiments. In his later life, he took a tutoring position that allowed him to travel throughout Europe, where he met other intellectual leaders of his day. Smith then returned home and spent the next ten years writing The Wealth of Nations, publishing it in 1776. He died in 1790 at the age of 67.