You have got to give it to Jon Stewart. A core group of high-ranking military officials called for Donald Rumsfeld's resignation as Secretary of Defense, but Stewart? He remains a charming and respectful interviewer.
Rumsfeld appeared on the show to promote his new book Known and Unknown: A Memoir. As a memoir, Rumsfeld traces his political path to becoming Secretary of Defense and to making controversial decisions that would shake/confuse/excite/infuriate a nation.
The Amazon site notes that proceeds from the book go to the military charities supported by the Rumsfeld Foundation.