FROM JEFF DUNTEMANN:  Dreamhealer.

By day, Larry Kettelkamp keeps ancient PDP-8 computers alive in a collapsing industrial bakery. By night he wages war on nightmares, and has been waging that war for thirty years. As a young man, Larry discovered that he could enter other peoples’ nightmares, end them, and then vaccinate the dreamers against that nightmare with an ancient symbol that alters the relationship between the two hemispheres of the brain.
For nightmares are not random concoctions of our dreaming imaginations. Strange creatures called archons living in the subtle realms of the collective unconscious craft horrifying dreams to drop into sleeping minds, and then feast on the terror those dreams evoke. This scheme goes back 15,000 years, to the dawn of human history. It was created by a sort of super-archon who claims to be the Demiurge of ancient Persian myth.
Once Larry learns how to destroy archons instead of merely banishing them from dreams, this architect of all nightmares hunts Larry down and demands that Larry stop destroying the monster’s archon servants. Thus begins an escalating conflict that draws in a bored title-search agent, a witch and a lightworker, two teenage prodigies, a modern-day cult practicing ancient Persian death magick, dream mechas a quarter-mile high, and a very very large number of dogs.