CAMEA is an indirect geometry spectrometer conceived by a Danish (Copenhagen University, Technical University of Denmark) and Swiss (École Polytechnique Fédérale de Lausanne, Paul Scherrer Insitut) Collaboration for the European Spallation Source (ESS), Lund, Sweden. The CAMEA instrument concept has been selected for construction at the ESS, subject to a feasibility study. This document is the final report for the concept phase of the CAMEA instrument project for the European Spallation Source. The material contained within this report represents updated versions of all of the reports submitted for the instrument proposal to the ESS, from which CAMEA was selected for construction.