This article discusses "Focus in High School Mathematics: Reasoning and Sense Making", a new (2009) publication of the National Council of Teachers of Mathematics (NCTM). Its message is simple: Reasoning and sense making provide a focus for high school mathematics that will give students a foundation for their future success. The publication argues that reasoning and sense making are foundational to all mathematical processes. For example, problem solving is impossible without reasoning, and sense making is inherent in making mathematical connections. A focus on reasoning and sense making places students' personal engagement in mathematical thinking at the forefront of high school mathematics. While building on NCTM's continuing vision for school mathematics, "Focus in High School Mathematics" provides useful new perspectives that may help form a consensus around the changes that need to be made in high school mathematics. Moreover, the publication is poised to become the model for continued work by NCTM and others to improve high school mathematics.