This began with SPI and an effort to use more fog of war than the Panzer Gruppe Guderian system was offering.
Based on the Wacht Am Rhein system, the thinking evolved into Operation Typhoon, our founding mother/father or whathaveyou and stemed into what is now known as the Victory in the West series that includes Pattons Third Army, Operation Grenade and Sicily: The Race for Messina.
I put the system through a filter and produced Iron Tide: Panzers in the Ardennes, after more than ten years of tinkering and delays in production. It lingered on the top ten at BoardGameGeek.com for over 3 years, just to show you that the popularity for the system and its offshoots still exists.
After many years of non-production, more and more offshoots of the original have come down the belt including the fabulous The Killing Ground along with its expansion Overlord, to give the system a complete D-Day simulation.
Numerous reprints by Command Japan, additional award winning games like Red Star Rising and now, on the horizon, another set of offshoot games is slated to appear if the preorder numbers are met.
Don't look for this to go off your radar real soon. I feel that the innovation is not complete in simulating within this system and its relatives. The best part is that it just keeps on coming.