“Every staircase goes up to the light” (I remember writing in my travel notebook, as a student, having visited LC’s studio in Paris on Nungesser et Coli street)… Of course, there are also stairs that can lead us to particular hells that each one has. Who does not remember those images of a staircase that goes down to the basements, to the darkness, to the deep, to the dark? Difficult, in any case, to separate stairs and skylights because, in many cases, they go together, one below the other. Either way, to be strict, there are stairs that do not have skylights and skylights and overhead lighting that do not illuminate any stairs. That is what has motivated us to separate the book into two large chapters. We have built few houses with a central patio as the plots in Catalunya are small, however many transparencies between the front and rear facades to generate permeability and appropriation of the exterior spaces near the house. Reviewing our work of these first 25 years, I deduce that all our effort has always been to make architecture more luminous. In bilingual Spanish / English.