Yes, the sale of rare books is legal as long as the books were obtained legally and are not subject to any restrictions or laws prohibiting their sale. However, there are some laws and regulations that sellers should be aware of, such as copyright laws, import/export laws, and laws related to the sale of antiquities or cultural heritage items.
In some cases, rare books may be subject to export restrictions or require an export license, especially if they are considered national treasures or items of cultural heritage. Similarly, some countries have laws restricting the export of certain rare books or requiring special permits or licenses for their sale.
Before selling a rare book, it is important to research any legal requirements or restrictions that may apply, especially if the book is particularly valuable or has historical significance. Sellers should also ensure that they have legal ownership of the book and are not selling stolen goods.
In general, as long as rare books are sold legally and ethically, there is nothing illegal about their sale.