"Company Internships" (PE), or external internships, constitute one of the main hallmarks of the training given at the ETSI of Mines and Energy of the UPM. Not in vain, aware of its importance, we were the first university center in Spain that opted, already in 1983, for the inclusion of internships as a mandatory subject in its study plans. During these almost four decades of practicing internships we have repeatedly confirmed the high incidence of this activity in access to the first job, its positive effect as a facilitating element for graduates' job insertion. ...