The Accountant is not based on a book. The Accountant is truly an original story. It was penned by screenwriter Bill Dubuque, who also transcribed the 2014 Robert De Niro led drama, The Judge. Dubuque’s script has been everywhere for a while, appearing on The Black List (an annual selection of the most popular unproduced scripts in Hollywood) in 2011, according to Nikki Finke of Deadline.