This is a detailed study of learning in the context of dry stone walling. It examines what happens in the learning situation. The aim of this work was: 'To understand the nature of expertise in dry stone walling, how it is understood by those practising the craft, and how it is transmitted to others'. The main research questions were, therefore: What happens when dry stone wallers are learning their craft? How do they acquire expertise in dry stone walling? How is this learning communicated? This process necessitated developing a way of engaging with the practitioners, eliciting descriptive data about what they were doing, and why they were doing it, through interviews (or conversations) with both individuals and groups, whilst they practiced their skill. Twenty three wailers were interviewed as they worked, building walls. The material obtained was analysed under seven different themes: 'Knowing how' The use of tacit knowledge or intuition 'Flow' Constant decision making, reflection and learning from mistakes Individual and subjective variations and experiences The relevance of emotion The use of 'rules of thumb' or maxims. Learning walling does not fit simply into any of the seven themes. It is contextualised, complex and individual. It demonstrates tacit knowledge and intuition. It involves emotion, sometimes consciously, sometimes not. It involves memory, problem solving, and learning from mistakes, and reflection. Maxims or 'rules of thumb' were a key element in the learning process at all stages. Linear stages of learning were not evidenced. Deep understanding of the practice is evidenced, and the wider learning and teaching implications are explored.