Of the various self-portraits Mateos painted, this one from 1967 is the last and the one that best sums up the sculptor's personality. His determination and strong character, passionate and true to himself, who does not understand half measures, are captured in this hard, serious gesture in which his gaze takes us to areas of intimate longing.

The expressionist treatment takes the form of certain more or less exaggerated and schematised features: the angle of the eyebrows; the wrinkles on the forehead summarised in a line; the volume of the chin, almost a volute; or the hair with a very marked volume... all evidence of the distance from realist figuration.

With them, the artist asserts the primacy of the artist's vision over the model, and manages to give the bust a hard geometric and linear character. These characteristics would define the work of maturity that was about to arrive, when this expressionism would turn into constructive analysis.