  In the last decade a lot of research activity focused on the use of quantum
entanglement as a resource for remote target detection, i.e. on the design of a
quantum radar. The literature on this subject uses tools of quantum optics and
quantum information theory, and therefore it often results obscure to radar
engineers. This review has been written with the purpose of removing this
obscurity.As such, it contains a review of the main advances in the quantum
radar literature accompanied by a thorough introduction of the quantum optics
background necessary for its understanding.
