### Mathematics Of The Incas, Ascher&Ascher

Glorious; breaks down what quipus possibly mean by looking at the
mathematical relations between their elements as well as what little we
know about their use in Inca society. You will want paper and pencil
to enjoy this book properly, or maybe a lot of string, because it
solidifies its explanations not just with detailed examples but with
exercises.

By security through obscurity, this is probably better secure
data-storage than a PDA or notebook; if 1970's fringe remains
fashionable you could even hide it in plain sight. Budgeting? Bets?
Hierarchal relationships? Remember what you need to remember and let
the past live.
So wrote clew in
Technology.