The study sets out to elaborate a universal contrastive model of modality and to apply it to the modal verbs müssen/sollen in German and dovere in Italian. Proceeding from a definition of modality as a propositional (speaker) attitude and from the three propositional attitudes of saying, believing and wanting, the study defines and establishes the three propositional domains assertion, evaluation, and volition. Depending on the nature of the asserting, evaluating or volitional agent, various types of modality can be identified in each of the three modal domains. Sets of sentences containing müssen/sollen and dovere are analyzed in terms of these criteria and examined for the specific functions they perform.