A man wakes up in ragged clothes in a back-alley with a headache, no memory and an equally shabby companion who assures him that this is an everyday occurrence. What distinguishes Luke, hero of Ken Follett`s effective new thriller Code to Zero, is that he realises so very rapidly that the absence of any desire for alcohol means that he is being lied to. Smart and resourceful, but no superman, Luke`s personal memories are gone, but his skills are still there--skills he realises he learned in WW2. Follett`s sense of the conflicts and loyalties of the late Eisenhower 50s, with Sputnik in the sky and its American equivalent about to launch, is spot on; he is excellent on the game of shadows played by the early CIA men like Luke`s old friend turned enemy Anthony, and the reasons why some people retained treasonable allegiance to Stalinism for so long. His management of shifts of time and viewpoint is slick and professional, but he also remembers what all this is for; the back story of Anthony, Luke, Luke`s wife Elspeth and Billy, the woman whom Luke once loved and who holds the key to his mind, is intensely credible and moving.