Research suggests that when young children have many opportunities to write they start believing they are the sort of people who can write for intellectual, academic, and social purposes. They also learn foundational reading skills. Project-like compositional writing involving design, strategies, and problem solving versus functional writing or shorter writing episodes, promises even more benefits. A question for teachers is how might we motivate young children toward complex projects when they are still learning basic literacy concepts. We take up this problem by focusing on the conditions under which young children might be motivated to write, specifically through the lenses of self-determination theory and engagement. We suggest that making books, a complex compositional activity, linked to shared reading and study of multimodal picture books, combine for a vigorous social practice where children's motivational needs can be met. We offer practical recommendations for facilitating motivated, engaged writing in a classroom.