"The Two of Them," is, I am sorry to report, a failure as science fiction. Nominally a parallel-worlds adventure, most of the action takes place on Ka'abah, a planet that has apparently based its racist, male-chauvinist culture on the traditions of the Arabian Nights tales. The protagonists are two undercover agents, working for a shadowy agency called the Trans-Temporal Authority, or more familiarly, The Gang. No one, including the agents, knows what The Gang is really up to.
This murkiness is intentional; Miss Russ wants the reader's attention elsewhere. Her main concern is the feminist rebellion of agent Irene Waskiewics….
If Miss Russ were trying to create fully rounded, believable characters, Irene's odd mixture of compassion and cold-bloodedness might strike a false note. But Irene and Ernst [her fellow agent and her lover] are not characters at all; they are arbitrary assemblages of characteristics, cobbled together to advance an ideological point. In general, I am not opposed to such an esthetic strategy; what really flaws the book is that not only Ernst and Irene but also the "exotic" settings on Ka'abah are so deadly dull. Even an implausible adventure story may serve as a vehicle for a valuable message; but an adventure story that fails to hold the reader's interest is simply excess baggage.
Gerald Jonas, "Fiction: 'The Two of Them'," in The New York Times Book Review (© 1978 by The New York Times Company; reprinted by permission), June 25, 1978, p. 22.