The essay tackles the treatment given to the library as a social institution by the Brazilian Constitution and the State Constitution of Piaui. The confirmed omission found in these major documents in relation to such institution, stands as a paradox requiring to be discussed, given the relevance of information in the contemporary society and the fact that, libraries, coupling with the expansion of the electronic information networks, continue to maintain the fundamental mission of preserving, disseminating and retrieving information, besides supplying it in response to the populations' demand. It further emphasizes the need for information professionals to be aware of their social function, in presence of the changes occurring nowadays.
library and constitution; omission in constitutions; brazilian constitution; state constitution of Piauí