Why is alignment so important? What difference does it make if textbooks include activities that are not aligned? The Benchmarks for Science Literacy and the National Science Education Standards include in their science literacy recommendations a number of important ideas that are not easy for students to grasp. These include fundamental ideas and teaching for student understanding of these ideas requires time. To do this effectively, teachers deserve textbooks that directly support teaching and learning of the specific ideas recommended in the Benchmarks and the NSES.