David Brin is fairly well known for his hard science fiction, though he has taken side trips into fantasy. This is his first one, with Glory Season being the second. Though The Practice Effect is more successful, it, like Glory Season, drops the ball with the ending -- though not nearly as badly. Anyway, don't let that stop you from reading this one, as the trip is worth the slight letdown of the ending!

It is some point in the near future; humanity has developed Zievatronics, a method of generating 'doorways' that, they believe, open up into parallel universes. One of the world's experts on this technology, physicist Dennis Nuel, has been removed from overseeing the project due to office politics. But something goes wrong, and he's maneuvered into going through the doorway to investigate the problem. From there, things get really weird.

I actually can't say too much without spoiling the TFs. And there are lots of them, though they certainly aren't typical of what most people think of as TFs. The characters are well drawn, the world is well worked out (though it is a bit cliche-ish), and, unlike most fantasies, technology does change the world. Apparently this is one of David Brin's pet peeves...

The novel's a fun read, with good characters, exciting chases, and a mystery that makes no sense in terms of conventional physics. There are lots of panics, death-defying escapes, applications of science. All this creates a wondrous endeavour that turns typical fantasy on its head.

Regardless, even with the ending, it is a fun read. It leaves one with a warm feeling, and should generate lots of ideas. What more can one ask?