Seth L. Riley at The Millions:
The ultimate tragedy of Under the Volcano is that of humanity’s wasted potential. Can, Lowry pondered, the psyche repair itself? We are capable of such great things, yet we choose mollification and comfort over almost anything—sometimes even over life itself. “I love hell,” Firmin claims. “I can’t wait to get back there. In fact I’m running, I’m almost back there already.” Under the Volcano is Firmin’s attempt to reckon with himself. He is alone, alienated and is finally unable to square himself with the world he has built for himself within the world he has, in many respects, stolen from others. And, in this, he has everything in common with those around him but, from Firmin’s point of view, the other characters are often reduced to minor characters, walk-ons. The only character that truly comforts Firmin is the beverage waiting before him. This minimization is not only Firmin’s: Each of the novel’s characters, in different ways, attempts to reduce the other to satiate the self.