A book hound is essentially a hobbyist who collects rare books, usually first editions at well under retail price and sells them at a price much closer to their actual value. The old adage that "one man's junk is another's treasure," can apply to this hobby/business venture. Whether some people just don't know the value of what they are losing or if they simply have no choice in losing property rare books can be found at ridiculously cheap prices. Though it might be akin to finding a needle in a haystack, they can be found.
The first place to look for rare books are garage sales and flea markets. Searching through dusty old boxes of books might find net a first edition hardcover in sellable condition. Books with the original dust cover are typically worth more.
Another place to look for first edition books are estate sales or auctions. Many auction houses allow bidders to prescreen lots a day or two before the auction to allow buyers to map out their bidding. Often times books are sold as a "box of books." If you want to buy a book specifically in that box you'll get the rest of them as well.
For the experienced or novice book hound there are some very valuable resources to make your endeavors more lucrative. The first resource is pricing guides. This will give you current values and an idea of what to sell them for. More important than pricing guides are guides in how to identify first edition printings or more importantly, rare misprints. Other valuable information might include author pen names. Books written under a pen name can be even more valuable than books written in the author's own name.
It doesn't matter if book hounding starts out as a hobby or becomes a lucrative enough of an investment to become an income one of the keys to success will be the ability to identify and evaluate your finds.
There are also guides to show you how to evaluate the condition of your book, check for damage, and how to accurately describe your find if you decide to sell it at an online auction. If you have a passion for bargain shopping, history, literature, or reading you might just be an answer to the question of what is a book hound.