The purpose of copyright registration is to place on record a verifiable account of the date and content of the work in question, so that in the event of a legal claim, or case of infringement or plagiarism, the copyright owner can produce a copy of the work from an official government source.
 Before 1978, in the United States, federal copyright was generally secured by the act of publication with notice of copyright or by registration of an unpublished work. This has now been largely superseded by international conventions, principally the Berne Convention, which provide rights harmonized at an international level without a requirement for national registration. However, the U.S. still provides legal advantages for registering works of U.S. origin. For example, a registration, or a refusal of registration, is required before an infringement suit may be filed in a US court and registration is required for claiming statutory damages in most cases.
 It is a common misconception to confuse copyright registration with the granting of copyright. Copyright in most countries today is automatic on "fixation" – it applies as soon as the work is fixed in some tangible medium. This standard is established internationally by the Berne Convention (1886), which most countries have signed onto since.  Registration may be required by countries before joining Berne. For instance, the US required registration of copyrighted works before it signed onto the Berne Convention in 1989; at that point, registration was no longer required for works to be copyrighted in the US.
 The observation that registration is not required in the United States, however, has been described as misleading.: 86–87  This is partly because registration remains a prerequisite to filing an infringement suit,: 87  and also because important remedies depend on prompt registration—such as attorneys fees and statutory damages.: 90  At least one commentator has questioned whether the conditioning of legal recourse on registration is inconsistent with the United States' obligations under the Berne Convention regarding "formalities".: 90 n.11 
 
Some scholars and policy advocates (such as law professor and activist Lawrence Lessig and U.S. Representative Zoe Lofgren) have called for returning to a system of registration requirements and possibly other formalities such as copyright notice.  The system of automatic copyright on fixation has been cited as one of the factors behind the growth of so-called "orphan works" in, for instance, the U.S. Copyright Office's 2006 report on orphan works.  UC Berkeley's Law School held a conference in 2013 on the question of "Reform(aliz)ing Copyright for the Internet Age?", noting that  "Formalities, which in the past three decades have largely disappeared from American copyright law, may be about to stage a comeback. ... [R]ecent research on formalities suggests that we can get many of the benefits that formalities promise for a more efficient and focused copyright law, without the problems that led us to do away with them in the first place." All United States copyright registrations and renewals registered since 1978 have been published online at the
Copyright Office website. Registrations and renewals prior to 1978 were published in semi-annual softcover Copyright Catalogs. For films from 1894 to 1969, inclusive, Library of Congress published hardcover Cumulative Copyright Catalogs, each covering ten or more years.
 Please see the Copyright Catalog article for links to download digital copies of these pre-1978 US catalogs.