K-12 mathematics education has undergone many changes over the past decades, sometimes driven forward by mathematicians, sometimes by mathematics educators. Those two groups have often disagreed, but we are now in a more cooperative period in which experts on both sides seem to agree more and argue less. But in reaching this rapprochement, we have left out another group of experts who offer valuable perspectives and fresh ideas--the K-12 mathematics teachers themselves. In doing so, we not only miss the opportunity to draw on different expertise but also inadvertently demean the teaching profession itself. [For the complete volume, "Mathematics Matters in Education: Essays in Honor of Roger E. Howe. Advances in STEM Education (ASTEME)," see ED607653.]