A few months after our beloved Belén passed away, a group of colleagues and friends from the Faculty decided to give her what we considered a well-deserved tribute in the form of a book. From the outset, we agreed that it wasn't simply a matter of compiling a series of academic works by specialists in the subjects of her research interest, but that we also wanted to include contributions of another nature, such as biographical sketches, recollections, or creative writings that evoked her, given that the intended recipient of this work would be her son, Eduardo Díaz Castro.