He subsequently made his living in information technology while writing books on chess and researching its history.
As well as The Oxford Companion to Chess, Whyld was the author of other reference works such as Chess: The Records (1986), an adjunct to the Guinness Book of Records and the comprehensive The Collected Games of Emanuel Lasker (1998).
From 1978 until his death in 2003, Whyld wrote the "Quotes and Queries" column in the British Chess Magazine.
A number of chess historians, including Dale Brandreth, Frank Skoff and Edward Winter, all of whom had close contact with Whyld, came to question his reliability and bona fides on certain issues.
Whyld's library was later sold to the Musée Suisse du Jeu, located on the shores of Lake Geneva in Switzerland (as reported in number 152 of EG).