This chapter investigates how abstraction, concretion and the respective capacities are related to action and knowledge as the main subject of this essay. The entire action appears as a connection of abstractions and concretions that described in the following compilation: The action plan describes the abstraction that relates the identified objects in the given situation with the intended objective of the action. Nevertheless the presented approach addresses both abstraction and concretion: abstraction is extended in terms of task representation while the design of the KMS influences the user's concretions such as organizing their task, creating tasks during work activities, and thus implicitly explicating their knowledge incorporated in action. Moreover, it is shown how the analytical standard analysis of knowledge is related the concept of knowledge as rational capacity. However, several recent studies support the view that knowledge possesses a dynamic nature that cannot be easily transformed into knowledge artifacts.