This book is about traditional tango dance music - that is, the music recorded by dance orchestras in Argentina between the late 1920s and late 1950s.It's mainly a resource for new, inexperienced or even reluctant tango DJs - people who are taking responsibility for providing the music for dance events. It suggests a 'starter collection' of five hundred songs, arranged into ready-made tandas, intended to present the best orchestras and singers, and with the content weighted according to the relative importance of the different orchestras and representing their best periods.Even if you are not a tango DJ this approach (focused directly on tango music as it might be danced) will be interesting for anyone who wishes to know tango music better, or who is open to suggestions as to what is good for dancing (and listening).