This chapter provides an inventory of the subject matter knowledge on which Sarah drew for the content of her teaching. The teacher's subject matter knowledge, no less than other areas of her knowledge, is practical knowledge, shaped by and for the practical situation. To demonstrate this, it looks at the conceptions which underlie the different facets of content, the ways in which content from different subject matter areas is selected and combined, and at how this content changed as Sarah used it in teaching. Sarah herself remarked that "teaching English is such a diffuse thing"; it is not surprising that her conception of the subject matter of English is equally diffuse. The evolution of Sarah's conception of skills is most interesting. When work began on the Learning Course it was called the "Thinking Course". Sarah saw the skills and techniques she taught as applicable to a range of real situations and materials.