Relentless - Dean Koontz

Being a writer is a dangerous business.
Hostile reviews may have hastened the deaths of some authors, and Cubby Greenwich obsesses about the scathing review of his latest bestseller by Shearman Waxx.
A feared critic, with an aura of mystery about him, he's deemed an arbiter of taste.
An unexpected encounter with Waxx startles Cubby, but what should be a mildly embarrassing incident triggers an inhuman fury in the critic, who becomes bent on destroying Cubby.
Waxx is not merely a ferocious literary enemy, but a ruthless sociopath.
And for Cubby and his family, forced into hiding, the terror has just begun...it will be relentless.
Cubby's worst fears seem naive - he has no idea how to save himself or, more importantly, his wife and son...