The biofuels world is abuzz with talk of high octane fuel. Ethanol trade groups weighed in recently with regulators on the role of higher octane fuel in meeting fuel economy targets. Their interest in gasoline and fuel economy might seem odd, except that their plan is to deliver higher octane gasoline by increasing the amount of ethanol blended into it. Octane is a confusing, technical topic with complex implications for ethanol and vehicle efficiency. Depending upon whom you ask, high octane gasoline blends with more ethanol are either critical to enable cars to deliver much needed fuel economy improvements, or a dead-end strategy that Congress should block, by requiring ethanol blends never exceed 10 percent. As usual, the arguments of the most extreme partisans on either side lean towards hype, so here are the 9 things you need to know about high octane fuel, and my perspective on a path forward.