The generalization of the electric-magnetic duality to the case of higher rank gauge potential Aμ₁... μ_{p + 1}. This kind of field appears in different supergravity and superstring models as fundamental massless states in the bosonic sector of the spectrum, e.g. in D = 11 supergravity one finds a p = 3-form potential [1], while D = 10 Type IIA supergravity exhibits a triplet p = 1, p = 2, p = 3 of gauge forms [2]. The index structure of tensor gauge fields allows them to couple in a gauge invariant way to spatially extended relativistic objects, i.e. p-branes which are present in the spectrum of supergravity models: they represent solitonic, exact solutions of the classical field equations [3]. Higher rank gauge potentials and p-branes seem to “embody”, in a natural way, both perturbative and nonperturbative aspects of the their common supergravity “mother theory”. The p-duality bridges the gap between different rank(dimensionality) fields (branes) within a given quantum field theory .