Buying a Car at Auction

I have heard from a fair few people that buying a car at auction is a great way to get a bargain on your next car. When considering buying a car at auction I have often been put off by the huge number of scare stories I have heard about “cut and shut” cars and stolen vehicles. So I was considering buying a guide to car auctions but what would be better would be if someone had written a free online guide to this. If anyone knows of one please let me know as I really think there is an opportunity for a bargain at these auctions.