This article is the first thorough examination of the Thai handbooks that are produced to explain agricultural and environmental knowledge. These khu-meu (handbooks) and tamra (textbooks) come into use when knowledge is moving from one party to another. They also establish symbolic correlations within the human, terrestrial world, or between the human, terrestrial world and the worlds of the gods, spirits, ancestors, or the unseen. Despite the fact that handbooks are pervasive for the organising, preserving, retrieving, transmitting and consuming of knowledge throughout the Southeast Asian region, there has been very little concerted study of handbook knowledge. Our analysis of environmental handbooks in Thailand shows that simplified mastery is a common goal of the handbook genre in both its "how to" and "reading signs" forms. The knowledge captured by the Thai language handbooks is of a practical, predictive kind and suited to particular circumstances. Such knowledge can ultimately bridge and blur the dichotomy between scientific and local epistemologies.