When studying aims and programs for elementary schools historically, we find that knowledge and skills have been among the dominating factors in the elementary school curriculum throughout the last century. The terms knowledge and skills usually are defined as basic skills which children are supposed to learn at school. In the USA, the basic skills also have been called the three R's, synonymous with arithmetic, reading, and writing. Because competence in the basic skills is a prerequisite for knowledge acquisition of other school subjects, e.g. science, history, etc, it is important that the learning and instruction of the basic skills are adapted to students' needs and readiness. As the three R's are fundamental and significant skills for children's learning and progress in other subject matters, systematic learning and training in the these basic skills are afforded much space and time in the children's curriculum during the first years of schooling. Although several common traits can be found among the three R's, this book concentrates on giving an outline on research in children's learning and performance of writing, and to some extent of reading.