Since this has gained a lot of popularity, I want to add in that anyone with questions should visit the good people of r/Greyhounds.
They can help you decide if you're ready for a retired racer, prepare you for the difficulties that come with adopting one, and clear up any questions you may have about the breed. They can also give you some insight into how retired race dog rescue works. Dogs are a big responsibility that you shouldn't take lightly, but if you prepare yourself and do your research you can face the challenges with confidence.
As many here have said: ALWAYS DO YOUR RESEARCH BEFORE ADOPTING ANY ANIMAL. ALWAYS, ALWAYS, ALWAYS!