"The Motley Fool Investment Guide", from 1996, not because it's particularly great (it's not), but because it got me into regular, sustained investing over time

"The Motley Fool Investment Guide", from 1996, not because it's particularly great (it's not), but because it got me into regular, sustained investing over time, and was where I first encountered the quote (mis?)attributed to Einstein: "compound interest is the most powerful force in the universe."