Kunhardt wrote nearly 50 books , including one of the bestselling children 's books of all time , '' Pat the Bunny , '' which has sold over six million copies . She had initially written it for her youngest child Edith . Other works include '' Twenty Days , '' an account of Lincoln 's assassination and the twenty days that followed , which she wrote with her son , Philip B. Kunhardt , Jr. ; '' Tiny Animal Stories '' ; '' The Telephone Book '' ; '' Lucky Mrs. Ticklefeather '' ; '' Brave Mr. Buckingham '' ; '' Junket is Nice '' ( 1933 ) ; '' Wise Old Aard-Vark '' ( 1936 ) ; and '' Now Open the Box ''
Lincoln 's assassination
Assassination of Abraham Lincoln
Dorothy Kunhardt