I flew in the navy and Marines, the flight (NATOPS) munuals were written in blood from the accidents that occurred.
I worked with a guy on a summer job who grew up with Gus Grissom, he spoke very highly of him.
“Written in blood” might be an apt subtitle for a history of human progress, and what humans do (and do not) learn from our mistakes...
38 years a firefighter, I can testify every page of the Fire Code is backed up by a pile of bodies somewhere...