Typically, dynamic systems are modelled and analysed quantitatively, for example with differential equations, and system simulation is carried out numerically. In contrast to this, qualitative reasoning and modelling is an area of Artificial Intelligence where modelling, reasoning and simulation are done qualitatively, without numbers. In such an approach, the velocity of a car may be “high”, or “low”, etc., and it may be increasing or decreasing. In this lecture, an approach to qualitative modelling and simulation based on qualitative differential equations will be introduced. It will be shown how a qualitative model of a systems can be automatically learned from observed quantitative behaviours of the system. The techniques will be illustrated by applications to robot learning, and to reconstructing human operator’s skill of controlling a crane.