ISBN, legal deposit and taxes
What to know when you publish on your own.
What an ISBN is
The code that identifies an edition: one ISBN for the paperback, another for the ebook, another for a new edition. It is not required by law, but bookshops need it to order your book.
Where to get one
From your country's ISBN agency (in the US, Bowker; in the UK, Nielsen; in Italy, isbn.it). Some sell single codes, some only blocks. The alternative is the free ISBN of KDP or of your distributor, who then shows as publisher.
Legal deposit
Many countries ask the publisher of a printed book to send copies to the national library (for example the British Library in the UK, the Library of Congress in the US through copyright registration). When you self-publish, you are the publisher: check your national library's rules.
Earnings and taxes
Book earnings are income and must be declared. The rules depend on your situation: ask an accountant before your first payment.
Prices, percentages and rules change: always check the official pages. Guide updated in October 2026.
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