My study of 300 Swedish teachers in primary school grades 1-3 (Alatalo, 2011), showed that too many teachers lack understanding of children's reading and writing development. A large part of the teachers in the study, had difficulties describing and reasoning about the basic elements of reading and writing instruction. These knowledge gaps cause difficulties for teachers to implement good reading and writing instruction. One consequence of this is that students, who are at risk for getting any kind of difficulty in reading and writing, are not identified as early as possible and thus do not get the support they need. Another consequence is that many teachers teach without knowing how their instruction actually affects student learning. What can the teacher education do to increase teachers’ knowledge of students’ reading and writing? It is not enough to know that learning occurs in interaction with others, because there are abilities that each individual himself must develop and master. Automated decoding, reading fluency and comprehension are neither abilities that necessarily arise by itselves, but usually require a proficient teacher’s systematic instruction (Moats, 2009; Snow, Burns & Griffin, 1998). Teachers' knowledge of the processes in students' reading and writing development are needed even more in the interactive learning process and in a time of rapidly emerging new technological tools for teaching. These skills can be said to be sustainable. My above-mentioned study (Alatalo, 2011) indicates that teachers, who have knowledge of the language structures, and know the meaning of phonological awareness, also have more knowledge of reading and writing in general. Specifically, it may mean that those who know the meaning of phonologic awareness also find it easier to understand processes that lead for example to reading fluency and comprehension. This is something that the teacher education should notice.