In this memoir, Mattis does not comment directly on the Trump administration, from which he resigned as secretary of defense in December 2018. But it’s clear from his resignation letter (reproduced in the book) and his persistent stress on the importance of stable, healthy alliances (which are not a feature of U.S. President Donald Trump’s volatile approach to foreign policy) that Mattis didn’t see eye to eye with the president. He is more forthright in his criticism of Presidents George W. Bush and Barack Obama: the first for being in too much of a rush to invade Iraq and the second for being in too much of a rush to withdraw. Mattis also blames General Tommy Franks for failing to capture Osama bin Laden at Tora Bora, in Afghanistan, in 2001, from where the al Qaeda leader managed to escape to Pakistan. The book’s main concerns, however, are the practical and ethical challenges of military leadership. Mattis draws on his deep professionalism and knowledge of military history in describing the stress of battle and the tough decision to send soldiers into the field to kill and be killed.