Cooking the books refers to the illegal practice of manipulating financial records and committing fraud or embezzlement in the hopes of monetary gain by individuals as well as organizations or corporations.
The roots of the expression lie in the 17th century use of the term “cook” which in this case was synonymous to “falsify”.
First cases of the phrase “cooking the books” emerged in the late 18th century and early 19th century, however the expression wasn’t widely known until the 1880’s.
“Cooking the books” would turn into a well-known phrase, and practice many resort to in order to gain extra dollars at the expense of others.
During the 20th century, people have been widely exposed to the expression, turning it into a colloquial phrase, used and understood by many.
It was first defined on Urban Dictionary in 2004.