Suspense abounds in "Horse Under Water". It is not of the rat-tat-tat, double-barrelled-action variety, but rather a subtly disturbing quieter kind of tension. The impatient reader wants Len Deighton to get-on-with-it and resolve an expounded situation … while, paradoxically, this same reader insists that Deighton not omit a single detail en route. In his earlier, highly popular, "Funeral in Berlin", and "The Ipcress File", Deighton employed the same formula. In fact, in classic suspensestory style, it is not until very near the end of "Horse Under Water" that the by-now-befuddled reader has any inkling what the whole thing is all about … nor is it until virtually the final page that the mystery IS unravelled.

We seem to be living in a decade that is fortuitous for the spy story afficionado. Deighton's operations compare to those depicted by Le Carré and Ian Fleming. His writing is without the extra gimmicks of James Bond. True, there are girls … and there are cars, and food, and weapons, and international settings. None of these, however, intrude upon the main action. Character development is, happily, an integral part of the Deighton technique. At all times, the discerning reader is directly involved in a game of matching wits with Len Deighton and his nameless hero … even to a clever puzzle linking Chapter headings with Table of Contents. (p. 388)