Under the National Library Board Act (Chapter 197, No. 5 of 1995, Part II Section 10), two copies of every publication published in Singapore have to be deposited with the National Library Singapore within four weeks from the date of publication. Through legal deposit, all works by Singapore writers, producers and publishers can be collected and preserved. This booklet explains what is legal deposit, how to deposit, benefits to publishers, as well as services for publishers relating to ISBN, ISSN, International Standard Music Number (ISMN) and Cataloguing In Publication (CIP).