A vade mecum—literally “go with me”, in Latin—is a handbook or reference that is readily available for consultation.
Here you’ll find my own vade mecum, a motley collection of notes, observations, definitions and cheat sheets, that I hope you find useful. It is inspired by things I get asked about a lot and the contents are largely taken from my personal lab books, research notes and journals.
Corrections and contrary advisements are welcome in the comments.