Abstract. In this chapter, we present an overview of mobile guides that rely on maps or map-like representations in providing their services. We discuss technical issues as well as problems related to human factors that mobile guides have to cope with in order to assist their respective users. The main part of the chapters describes a number of relevant systems in the field of mobile guides, ranging from influential work such as Cyberguide to systems that offer unique services such as TellMaris. The comparison is based on the issues we identified initially. We conclude with an outlook on future directions such as collaborative usage, new means of interaction and further personalisation of mobile services.