Many of us who were active at Story Games spent hours - and pages - interrogating Eero Tuovinen about his practice of "challenge-based" wargame old-school play. There were wonderful and insightful discussions, which, unfortunately, were all lost when the forum shut down.
Well, great news! Eero is back at work publishing an actual "primer" covering this kind of play. It's both theory and praxis.
His perspective here is well developed, unique to his particular approach to this style of gaming, and based on years of actual play.
I highly recommend you to check it out, to see what all the hype was all about. He's looking to fund it here, at IndieGoGo:
Help spread the word, too - it's just word of mouth at this point, and I'm sure you have friends or contacts who would really enjoy this product.