We define in a global manner the notion of a connective structure for a gerbe on a space X. When the gerbe is endowed with trivializing data with respect to an open cover of X, we describe this connective structure in two separate ways, which extend from abelian to general gerbes the corresponding descriptions due to J.- L. Brylinski and N. Hitchin. We give a global definition of the 3-curvature of this connective structure as a 3-form on X with values in the Lie stack of the gauge stack of the gerbe. We also study this notion locally in terms of more traditional Lie algebra-valued 3-forms. The Bianchi identity, which the curvature of a connection on a principal bundle satisfies, is replaced here by a more elaborate equation.

78 pages. Uses XyPic. A number of significant additions have been incorporated into this version. This includes a description of the coboundary relations in full generality, as well as a Cech-de Rham interpretation of the cocycle and coboundary relations for the 3-curvature of a gerbe with connection. New and more conceptual proofs, which make use of bitorsor diagrams, are given for most of these relations