As a consequence of the reverse-engineering approach to the mystery of the dark matter in galaxies that I advocate here, the future is the past. Namely, I argue that, in the observational properties of galaxies, there is much of the required information to solve the riddle. Unfortunately, we have recovered only a very small part of it, not because it is difficult or long to do, but because we were stuck in a different paradigm where, honestly, all this phenomenology is not so important.
However, the situation is extremely positive because, in the near future, from Gaia to SKA, we will be submerged by an enormous flux of information, coming from different messengers, on all aspects of galaxies, independently if one believes or not that this will lead to a solution of the old mystery of dark matter.
I thank Francesca Matteucci for motivating me towards the enterprise of writing this review. I thank N. Turini, V. Gammaldi, F. Nesti, M. Cobal, A. Bressan, M. Cappellari, G. Danese, A. Lapi, C. Frenk, C. Baccigalupi, A. Pillepich, M.F. de Laurentis, R. Valdarnini and C. di Paolo for very useful discussions. I thank Brigitte Greinoecker for help in the process of writing this review.