Prospéro (PROgramme de Sociologie Pragmatique, Expérimentale et Réflexive sur Ordinateur) is a free text analysis tool aimed at scholars in the Humanities capable of complex analysis on natural language. It permits users to classify and track records or thematic sets within a text or corpus for the purpose of exploration, analysis and comparison. It identifies places in a text that display uncertainty, controversy, criticism, and enables the user to establish rule and meta-rules to separate factual statements from views and interpretations. Prospéro is particularly designed for complex cases composed of large texts containing heterogenous discourse.