This Collective book on the Administrative Act, coordinated by Professor Ricardo Rivero Ortega, contains articles written on the subject by the following Professors: MARÍA JOSÉ RODRÍGUEZ (Argentina), SILVIO LUIS FERREIRA DA ROCHA (Brasil), WILLIAM BARRERA MUÑOZ (Colombia), ERNESTO JINESTA L. (Costa Rica), MARCOS M. FERNANDO PABLO (España), JAVIER A. ECHEVARRÍA VARGAS (Estados Unidos), GILLES J. GUGLIELMI (Francia), LUIS JOSÉ BÉJAR RIVERA (México), ELOY ESPINOSA-SALDAÑA BARRERA (Perú), GRACIELA RUOCCO (Uruguay) y JOSÉ LUIS VILLEGAS MORENO (Venezuela). The book also contains a comparative Law study on Administrative acts written by Professor Rivero Ortega.