Major book retailers like Amazon, ThriftBooks, and Bookshop.org are legitimate, well-established, and safe for online shopping. While they offer distinct benefits—such as ThriftBooks for affordable used titles, Bookshop.org for supporting independent stores, and Amazon for general convenience—they all function as marketplaces where the quality of the experience can vary depending on individual third-party sellers. We recommend checking seller ratings on marketplace sites and utilizing the built-in buyer protection policies if issues with item condition or delivery arise.