Some symbolic AI models for example BDI (belief, desire, intention) models are conceived as explicit and operational models of the intentional pursuit and belief dynamics. The main concern of these models is to provide a clear understanding of the functional roles of dierent kinds of epistemic and motivational states (beliefs, acceptances, expectations, intentions, goals, desires etc...), of the relational properties among them. Mental congurations of appraisal (involving dierent kinds of motivational and epistemic states) which correspond to particular cognitive emotions such as disappointment, fear, relief, shame etc... have been analyzed by several authors close to the BDI theoretical tradition. The main objective of this work is a conceptual and theoretical clarication of the functional role of Surprise in a BDI-like cognitive architecture. In the paper dierent kinds of surprise are discussed and their properties analyzed. Each type of surprise is associated with a particular phas...