A b o u t six or seven years ago there was a “technological break­ through” at The RAND Corporation in the art of doing Systems Analysis and Military Studies. This technological breakthrough was of so simple and common-sense a nature that some readers will be annoyed at me for even inferentially claiming a patent for RAND, and others will be annoyed that I used the grandiose word “break­ through.” Both annoyances are probably justified, but it was never­ theless a very important event for RAND.