Even before the end of the war, in 1863, Cooke wrote the first of several popular biographies, that of Stonewall Jackson: A Military Biography, published in 1876, for which he received some contemporary criticism for the errors in the book. He also later published a novel on Jackson, "Surry of Eagle's Nest" (1866). His later efforts at biography, such as a biography of Robert E. Lee and officers that he had personally known, were considered more accurate that his early Jackson biography. In his declining years, his works showed the same style that he had used earlier and life, not showing any growth or development.