If you’re publishing a commercial book – that is, a book that you intend to sell and distribute outside of your circle of family and friends – you’ll need an ISBN and must provide a copy to The British Library. 

You don’t need an ISBN if you’re publishing a few books to give away to a small group of people; for instance, a published family history.

In order to sell a book, it must have an ISBN – International Standard Book Number – so booksellers can identify it amongst the many thousands of titles published in the UK annually, as well as in the international market. 

When a title is allocated an ISBN, the unique number allows libraries, bookshops and other publishers to catalogue and locate your book in order to fulfil an order or find out more it.

In addition to obtaining an ISBN, authors of commercial books have a legal requirement to provide a copy to The British Library. 

This is not just limited to books but also extends to publications such as pamphlets, journals and maps. 

When you do this, you preserve your book as part of Britain’s literary heritage, ensuring that it’s accessible to the public for generations to come. 

This requirement has been enshrined in British law since 1662; authors who publish a book become part of the UK’s rich literary history. 

The British Library is home to rare titles and first editions, and contains one of the largest collections of early Shakespeare editions. It also houses irreplaceable first drafts and personal papers from some of the leading lights of literature throughout the centuries, including James Joyce, George Orwell, Angela Carter and Hanif Kureishi.

Authors who submit a book to the British Library sit alongside these great names and many others. 

The process of sending your book, called Legal Deposit, also applies to electronic publications. However, if you publish both a print and digital version of the same book, you will normally only have to send a printed copy to the Library, although it may also request a copy of the e-book.

You must send the book within one month of it being published. 

The British Library is just one of a number of legal deposit libraries in the UK. Any of them are entitled to request a copy of your book. This includes: Bodleian Libraries University of Oxford, Cambridge University Library, the National Library of Scotland, the National Library of Wales and the Library of Trinity College Dublin.

No, the ISBN has nothing to do with the copyright of your book. The ISBN is how you sell your book and record how many copies you've sold. Copyrighting your book is a different process, which we talk about here.