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Abstract-Albeit the conception of relaying dates back to the 1970s, in recent years there has been an upsurge of search interest in cooperative wireless communications in both academia and industry. This article presents an easy-reading overview of the pivotal topics in both mobile station (MS) and base station (BS) assisted cooperation in the context of cellular radio systems. Owing to the ever-increasing amount of literature in this particular field, this paper is by no means exhaustive, but intends to serve as a roadmap for this area by assembling a representative sample of recent results and to stimulate further research. The emphasis is initially on relay-base cooperation, relying on network coding, followed by the design of cross-layer cooperative protocols conceived for MS cooperation, as well as on the concept of coalition network element assisted BS cooperation. Then, a range of complexity and backhaul traffic reduction techniques that have been proposed for BS cooperation are reviewed. A more detailed discussion is provided in the context of MS cooperation concerning the pros and cons of dispensing with high-complexity, power-hungry channel estimation. Finally, generalized design guidelines, conceived for cooperative wireless communications, are presented.