Museology is logical consequence of the importance of museums. They seemed to need a theory and, by the time, also a science of their own. Once with the fascination, it caused almost a hundred years of speculation ending with many museologies, tendencies, schools of thought and prominent theoreticians. Of course it was an error: the can be no science upon an institutional practice. Museology or, rather, Museography is an indispensable theory of a particularly important heritage occupation. The huge intellectual effort is not lost but will be inbuilt into the future science of heritage, or maybe of public memory.