The desire to enhance the thinking skills of learners has become a worldwide phenomenon. This desire has been further reinforced by programmes developed specifically for this purpose. Developers of these thinking skills programmes have made various claims about the effectiveness of their programmes in teaching learners general skills of thinking that can be applied to any field of study. The thesis presents a comprehensive examination of the four most prominent programmes. The basis of the thesis is a critical discussion of the assumptions underpinning these programmes and the coherence of their claims. At the core of these assumptions is the idea that thinking can be taught and learned free from any context. The idea raises important conceptual and practical issues that demand attention if improvements in pupils' thinking are to be addressed.