This paper introduces four categories of knowledge: "the folkways of teaching,""local mores,""private views," and "teaching expertise." The folkways of teaching describe "teaching as usual," learned and practiced in the half-conscious way in which people go about their everyday lives. Local mores constitute teaching knowledge held and used like the folkways and mostly based on them, yet local mores are more variable and likely to be articulated as maxims or missions. Teachers' private views are personally compelling, arising from the peculiar experiences, feelings, and characteristics of individuals. What marks off teaching expertise from the folkways, local mores, and private views is less what associated knowledge is about than how it is held and used. Although it can build on the folkways, teaching expertise goes beyond their mastery or skilled performance by including (a) judgments of appropriateness, testing of consequences, and considerations of ends rather than means, and (b) less typical modes of practice, such as explanation, discussion, and the deliberate management of value dilemmas. This paper analyzes, in detail, the "folkways of teaching," arguing that they are known by acquaintance, through participation, and as common sense. (Author/JD)