Newton Lowdown is a simple desk accessory (DA) for the Macintosh (will not work on other PCs, or Windows, I am afraid). To install it, simply drop it into the Apple Menu Items folder in your System Folder (if you have System 7 installed). If you are still using System 6, then you will need to use Font/DA Mover to install it in your System File, or use Suitcase or similar.
Newton Lowdown provide a quick desktop reference to NewtonScript™ commands which may be of use to those programming the Newton direct (e.g. through our NewtonScript Runner utility). It also guides you through the currently documented error codes, with a little help from Monty Python.