What’s a Daybook?

[The engineers had] been trained to keep an engineering daybook, a kind of journal in which they recorded what they did, things they’d learned, sketches of ideas, readings from meters, […] and sometimes just to doodle. […]

There’s an added benefit, too. Every now and then you can look back at what you were doing oh-so-many-years-ago and think about the people, the projects, and the awful clothes and hairstyles.