Another addition to the Heechee series (most recently Heechee Rendezvous, 1984), which has been growing steadily less involving--and this one is the dullest of the lot. Benevolent tycoon Robinette Broadhead, having died in Rendezvous, is now a machine-stored personality, and has become preoccupied by the problem of the Foe (or Assassins), pure-energy beings who. having caused the universe to stop expanding and start to contract (in the hope that the subsequent Big Bang will improve their life style), are hiding inside a black hole; Broadhead and the Heechee have set up the Joint Assassin Watch to keep an eye out. Eventually, of course, some Foe finally pop out to have a look around (they hide in the Ancient Ancestor pods carried by the Heechee), and, after scaring the daylights out of Broadhead, settle down to chat with Albert Einstein, one of Broadhead's data retrieval programs. It emerges that the Foe are not enemies at all, merely indifferent; and, by the time the universe starts to collapse, everyone--humans and Heechee alike--will be pure-energy beings anyway (like Broadhead himself). No plot, a subplot that fizzles, chunks of cosmological explication, uninteresting aliens, and thoroughly boring characters: one of the least engaging Pohls in many a year, and thus strictly for Heechee addicts.