Stross, Charles
Bob Howard is working on a desk job for the "Laundry", but he's bucking for field service. We meet him on his first trial, breaking into an industrial building to destroy the traces of a dangerous discovery a young mathematician has made. It turns out that certain kinds of math knowledge lead to the ability to summon demons from other universes -- the sort of thing once done with chalked pentagrams, but much more efficiently achieved with lasers instead of chalk, and with computers to keep track of the summoning rituals. It's the job of the Laundry to keep such knowledge under wraps.