Introduction Argyris and Schon (1974) first articulated the concept of theories of practice, and elements of the concept have become standard vocabulary in literature on organizational learning. Relatively few empirical studies, however, have explored the legitimacy of this concept for understanding how educators approach problems in their professional practice (Lipshitz, 2000). As accountability pressures for school improvement mount, the imperative for understanding effective school leadership behaviors makes the concept of theories of practice more appealing. The purpose of this article is to examine the structure of theories of practice as understood by Argyris and Schon and the implications for understanding the cognitive processes and behaviors that constitute effective instructional leadership in schools. The authors discuss a recent case study of successful school principals that mapped the principals' theories of practice of instructional leadership. The study illustrates the usefulness of the theory of practice framework for both research and improving professional practice (Houchens, 2008). Conceptual Framework Argyris and Schon's book, Theories in Practice (1974), explored the concept of organizational learning by articulating a rather elaborate framework that explained the cognitive structure and processes of problem solving that all people--not just professional practitioners--engage in. According to Argyris and Schon, theories are vehicles for explanation, prediction, or (p. 5). All humans, whether they are conscious of it or not, operate according to thousands of theories to explain their experience, predict future events, and control outcomes in various situations. All theories are situational, and based on an underlying set of values, beliefs and assumptions that frame an individual's perception of the world, which include assumptions about desirable outcomes for a variety of situations. Theories appear in an ... format: if the individual faces a particular situation, then based on the individual's core assumptions about this situation, the individual should take a particular action to either explain, predict or control the situation or outcome. Argyris and Schon called this if-then formulation a theory of action. full schema of a theory of action, then, would be as follows: in situation S, if you want to achieve consequence C, under assumptions a1 ... an, do (p. 6). Argyris and Schon went on to define theories of practice as special cases of theories of action that are rooted in problems arising in a professional's specific work context. Theories of practice describe routines, procedures and specific practices for dealing with problems common to the practice environment. practice is a sequence of actions undertaken by a person to serve others, who are considered clients. Each action in the sequence of actions repeats some aspect of other actions in the sequence, but each action is in some way unique. In medicine, for example, a typical sequence would be a diagnostic work-up, treatment of acute illness, a well-baby visit, chronic care, and consultation (p. 6). A theory of practice consists of a set of interrelated theories of action that specify for the situations of practice the actions that will, based on relevant assumptions, yield intended consequences. In addition to the basic theory of practice framework, Argyris and Schon identified models of how effective and ineffective learning takes place within individuals and groups. Because theories in use are (a) so deeply entrenched in the individual psyche, (b) usually subconscious to the individual, and (c) often at odds with espoused theories of action (how we say we behave to others or how we rationalize our behavior to others), they deeply affect the way individuals learn. Argyris and Schon (1978) described the typical, reflexive way we learn as single-loop learning, in which the individual sees that his or her behavior has not successfully resolved a problem. …