This is again one of Mr. Davies' low-keyed time teasers in which Howell who has last seen himself at seventeen finds himself five years later with a large blank space to be filled -- did he help to kill his father? who did murder his friend? and who is attempting to do away with him now? Sometimes it seems as if what he is doing next is what has happened before -- in a sense this is true of all of Davies' suggestible, suggestive stories which make these imperceptible transitions not only in time but also between science fiction and the mystery genre.