Early on in ["The Hydra Head"] an elevator attendant looks, as if for the first time, at the design on a Mexican peso—the eagle strangling the serpent. Toward the end, the narrator fantasticates the image in the service of explaining what the secret agent's trade is all about. The serpent is a hydra, and the agent is but one head of the hydra. Cut off that head and a thousand will replace it. The eagle is two-headed. "One head is called the CIA and the other the KGB. Two heads, but only one body. Almost the Holy Trinity of our age…. In serving one head we serve the other and vice-versa. There's no escape. The Hydra of our passions is trapped in the talons of the bicephalous eagle."

Or, put it another way,… the secret agent is trapped in a Manichean system in which there is an opposition of X and Y but not of good and evil. In dedicating his book to the memories of Conrad Veidt, Sydney Greenstreet, Peter Lorre and Claude Rains, Carlos Fuentes half lulls us into the expectation of a mere thriller, and the movie-buffery of the hero, Felix Maldonado, confirms that we ought not to expect much more than blood, the chase, the pedantic loquacity of Greenstreet villains. But the setting is a contemporary Mexico City drawn with the pencil of rage, and the issue is Mexican oil: "Like the Hydra, the oil is reborn, multiplied, from a single severed head…."

Dr. Fuentes is a distinguished writer, and distinction resides even in the mandatory scenes of violence, the enforced plastic surgery that robs [the protagonist] Felix of his identity, the philosophical expatiations (complete with quotations from Gide and Kirkegaard) we now expect from our distinguished villains, the ridiculous coincidences, the Greene-type observations: "The Indians, so handsome in the lands of their origin, so slim and spotless and secret, in the city became ugly, filthy, and bloated by carbonated drinks."

Perhaps the true distinction of the novel resides in its having forever dispensed with the possibilities of the spy thriller as a serious form.