This is a fabulous, well executed and complete simulator for the HP-67, available in universal binary for intel and PPC macs. If you've ever used any of the several RPN (Reverse Polish Notation) HP programmables, you likely love them. I have had three or four (HP-55, HP-41, HP-33,...); if you've ever used one, this simulator will be a natural.

- You can view and edit all registers and memory in easy-to-access text windows in addition to using the calculator keyboard and display.

- You can use the computer keypad for the common calculator functions (number entry, add, subtract, multiply, divide) or, of course, the mouse.

- It saves memory registers, programs and the complete calculator state to files for archiving projects. It has a nice "paper tape" simulator that doubles as a program listing window. Everything is very elegantly executed using Cocoa.

There's not much documentation, but if you have ever used one of these RPN programmables, you won't need any. And if you haven't used one, you probably won't be interested in this anyway. It just works (and has a nice mouse-over pup-up descriptions for all function keys and key combinations). And, the author has been very responsive to questions.

Really, this is a must have for you HP-RPN programmable lovers out there...