This technical report provides an evaluation of several possible languages and semantic formalisms that could be used in agent communication to play the role of a content language in the EU Agentcities.RTD project. The conclusions and background information may however be useful for agent developers more generally. This document includes a description of candidate languages, a list of criteria applied, evaluations of the five candidate languages and a final evaluation. The five candidate languages were DAML+OIL, ebXML, FIPA-SL, KIF and Prolog and the choice made for the EU Agentcities.RTD project was to develop services in KIF, FIPA-SL or both. Furthermore it is expected that the number and type of content language used in the EU Agentcities.RTD project will evolve over time as tests are carried out. The review process which led to the authoring of this document was carried out in the context of the Agentcities.RTD IST funded project (IST-2000-28385) and we would like to thank all project partners who contributed to it. The opinions expressed in this paper are those of the authors and are not necessarily those of the EU Agentcities.RTD partners.