Too many writers suffer at the hands of these two words.
Rack, as a verb, generally means to torture (rack my brains). As a noun, it can mean a variety of things, but the forms most often misspelled are those referring to an instrument of torture (The inquisitor planned to stretch his limbs on the rack.) or to be in a state of deep anguish (racked with sorrow). Rack as a noun also can refer to a frame, this its use as a verb in rack up points or rack billiard balls.
Wreak, as a verb, means to wreck (to wreak havoc). As a noun, it means ruin or destruction (Cleveland has been going to wrack for decades.).
The easy way to remember the difference is rack = torture while wrack, with an extra letter, goes the extra step of actually destroying something.
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My name is Rob Bignell. I’m an affordable, professional editor who runs Inventing Reality Editing Service, which meets the manuscript needs of writers both new and published. I also offer a variety of self-publishing services. During the past decade, I’ve helped more than 300 novelists and nonfiction authors obtain their publishing dreams at reasonable prices. I’m also the author of the 7 Minutes a Day… writing guidebooks, four nonfiction hiking guidebook series, and the literary novel Windmill. Several of my short stories in the literary and science fiction genres also have been published.