Retired US Navy Admiral William McRaven had an esteemed 37-year military career — which included leading the assassination of Osama bin Laden — but it was his time in Navy SEAL training after college that gave him his leadership philosophy.

In 2014, McRaven gave the commencement address at the University of Texas at Austin, breaking down the 10 biggest lessons he learned in the six months of Basic Underwater Demolition/SEALs training in his early 20s, and how they were universally applicable.

Now the chancellor of the University of Texas system, McRaven has released “Make Your Own Bed,” a short book expanding upon these principles he spoke about a few years ago.

In it, he recounts the last night of the Dive Phase of training — “the most technically difficult part” of training, McRaven said, and the one most likely to result in a serious injury or even death. It was the night he learned you must “be your very best in the darkest moments.”

The exercise requires that paired-off candidates swim two thousand meters underwater to a small ship, place a dummy mine on the bottom of it, and then return to the beach, all without being spotted by instructors.

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