 So what is lesson study? Well, lesson study really is an investigation into teaching. A collaborative investigation by teachers. So if you turn the words around, it's always studying a lesson. And it's framed by two things. A topic that teachers want to teach to. A student question, students are going to answer. And then a teacher question that they were about, what I mean by that is a research question. Another name for lesson study is research lesson. And so what do you want to learn about teaching through this lesson that you're going to teach? And so through that question, teachers gather evidence, which can be student talks, student work, student writing. And then they use the evidence to kind of answer the question. So an example may be that you may want to teach a lesson about Nat Turner. And the question might be for students, was Nat Turner a hero? Or was Nat Turner's revolt a success? If your question is Nat Turner a hero, you might want to think about, well, to answer that question, what kind of criteria do kids have for measuring or judging a hero? So how do you help kids develop a criteria? How do kids use criteria? You might investigate that question through the work on Nat Turner. And then ideally that lesson, what you learn from that lesson, spills over into the whole practice. So they might think, oh, whenever I ask them a valuable question, I need to make sure kids have it a criteria they're writing from. So is a form of professional development through which teachers not only develop effective lessons, but really develop their own content knowledge and they develop their pedagogies and really there's the central values of teaching? So unlike other kinds of professional development, which are driven by kind of answers, here's what a researcher found or here's what we found. If you do this in a classroom, it's going to excel happen, right? Lesson study is a little messier, but lesson study, because it's research, it's driven by questions and not answers. And so it's teachers generating knowledge about teaching through their context and their practice. So it kind of takes professional development turns on its head, right? It's teachers can be producers of knowledge about instruction, not just consumers of knowledge. Lesson study takes place very much within a context, within an historical subject focus, within a particular student focus and within the framework of a professional practice. So it's highly collaborative and highly democratic and this of course is what makes it very messy, but also very exciting. It draws teachers in. It asks them to be thoughtful professionals. And I've had teachers say to me, particularly people who teach at the elementary level in Oakland where we have high number of students who have low literacy skills with schools that are under threat of sanction because their test scores are low, where they have histories we kind of pushed out of the curriculum because of that. And they're given scripted programs to use and measured by how the fidelity, which they implement that program to teachers say to me, you know, when I work with colleagues and we do lesson study, I kind of remember, I can be thoughtful about my practice, right? I can remember that that's why I go into teaching. Now, that's a lot to say about one particular practice and I'm not saying that happens all the time, but at the bottom lesson study is this notion for teachers that they can contribute to the knowledge base about teaching and I think that's a really powerful democratic idea. And Stan, you said that it asks them to be thoughtful professionals and it's really, it also provides the context and it honors their professionalism and it honors their craft. And I think they, it's very validating. And at the same time that it honors teachers, it's not about teachers. It's not about what any individual teacher does in the classroom. It's about teaching the subject well and keeping the students in mind. And so by that I mean is essentially trying to understand what and how the students are learning.