As a bibliophile I have, on more than one occasion, sought to purchase books online that are not new and no longer available in most bookstores that deal in new books. Through a bit of digging around I was able to find some great sources of second hand books that ship worldwide.

The most well-known source for second hand books would have to be ebay. Ebay offers second hand book buyers a wealth of choice. You can find antiquarian delights as well as the latest bestseller mass market paperbacks on special at a fraction of the original buying price.

Many times people who want to read the latest book but who can't wait, will purchase a copy, read it and then put it straight up for sale, often recouping a significant proportion of their original purchase price. So if you are after the latest thriller and are prepared to wait a few days after release, you can often find a real bargain.

The second place I would recommend for purchasing second hand books I is Abebooks. Abebooks is where all the second hand book dealers who are online get together and display their wares. If you are looking for a title you can narrow a search down to paperback, hardcover (with or without dust jacket), new, pre-owned, signed or limited edition copies and so much more.

You can also narrow your search down to a particular country if you just want to search for copies that are close to you. Most sellers offer flat shipping rates that are cheaper than ebay and Abebooks has a seller rating system so you can buy with confidence.

The third place to look for books is Thriftbooks. Thriftbooks have their own warehouses but also, like Abebooks, are a marketplace for second hand booksellers. They focus on the more popular titles rather than older collectible items. They also deliver worldwide and have flat rates for shipping to overseas locations. You can search of a title and each book is organised by title, with each bookseller offering their price, generally matching each other. If you are in the US you can choose the warehouse or bookseller closest to you for a faster service.

Amazon also offer a great second hand book service. There are two rates of shipping to consider if you live overseas. The first is for those used books "Fulfilled By Amazon" which are shipped at Amazon's standard rates. The other used books are shipped according to specific dealer rates and can be more expensive than the regular "Per book" price offered by Amazon.

There are more sites of course that can offer great services, but ebay, Abebooks, Thriftbooks and Amazon are four of the biggest and the best.