Almost exclusively for physics majors or parallel-world addicts: a love-story involving bicameral minds, conscious subatomic particles, and traffic-jams on the parallel-universe freeway. On a business trip to Philadelphia during an electrical storm, computer-architect Katie Dunston falls in instant love/lust with music-publisher Briton Bell--who shares this bizarre, total mutual attraction. The affair continues back in N.Y., then on a trip to Katie's roots in Ireland--while Briton remains oddly guilt-free about his wife and kids back home. But physics prof Thomas Hanratty, who's invented a machine for commuting between parallel-worlds, knows that Katie and Briton are really from different worlds, having somehow met in a unique crossover action. (This happened because they're both such intensely ""bicameral"" types, with ""clear consciousness of left-hemisphere function."") Thus, when back in N.Y., Katie now finds that Briton Bell doesn't exist--though she's soon meeting an exact replica of Briton (same face, same name), an unmarried inventor who has designed a revolutionary new particle-physics-based computer. Rampant confusion ensues--for both Katie and the reader. She learns about the other Katie Dunston whom Prof. Hanratty has met in a parallel world. And eventually, after chunks of unrewarding lecture-material, Katie catches on to the secret of willful time-travel: ""If particles are conscious and can move in time, there must be the possibility of a link--the possibility that something in the mind can trigger the particles to switch. That something must generally be unconscious, but I can bring it out. . . under the agency of slow photons, and God knows what other forces, we can do it!"" So there's a brief reunion between the Katie and the Briton of different worlds--in a saccharine fadeout. An awkward mixture of hard science and softheaded romance, without the beguiling, non-technical fascination of the best parallel-world tales. (See, most recently, Jerry Yulsman's Elleander Morning, 1983).