If you publish a book January 1st 2018 can the copyright year still be 2017?

@MasterDvdC Meh, already had this discussion about a month ago ;) It depends on the country, and usually other things like the nature of the work/publication, and it could conceivably change in the future. Again not a lawyer, and for legal advice consult one, but Wikipedia has fairly comprehensive table: https://en.wikipedia.org/wiki/List_of_countries%27_copyright_lengths

In the USA, for example, anonymous, pseudonymous and works for hire have copyrights 95 years from year of publication, and to the very end of the 95th year. Hence if the work falls into one of those categories, you might want to get the publication year on the correct, next year since that one day would make one year of difference in copyright length. If it does not fall into one of those categories, there's still unlikely to be any harm from having it on the correct, new year. And registration can still be made after the infrigment, if deemed necessary, albeit yes you might want to ensure you have some way to prove authorship.

@Faust76 The rules I was stating were the rules for the USA as of at least 10 years or so, when I registered mine. Works for hire I don't know about. That would apply only if you were hired to do something. If it is something that you do, write, and then sell, or self publish, the rules are as I stated.

@MasterDvdC The question is still "Why though?" and the copyright length argument was already hashed out a month ago... But here's more hashing, then ;)

"The year of publication may determine the length of the copyright term for a work made for hire or an anonymous or pseudonymous work." (US Copyright Office) <- My post from last year almost a month ago.

If it becomes a classic and you happen to die withing 25 years of the publication, your publishing house and/or estate will almost certainly want to argue that it was "work for hire" . The work will also look like a year old/out of date. In addition the question did not specify whether it would be anonymous, pseudonymous or work for hire.

Ergo, backdating the publication would carry no benefits, it would almost certainly be detrimental, and it would let infriger argue that they thought the copyright is invalid because it's false. If, for whatever reason, it still was important to get previous years copyright date, then my suggestion of giving a "preview copy" to trusted associate, and preferably revising the work with feedback to get publication date on the new year as well, would probably be the best way to do it legally, publishing house allowing.

@steve717 A work is copyrighted from the moment it's created, so in general there's no such thing as "you copyright". In the US you could register it with the copyright office for proof, though that's not really a necessity, and the act of "publishing" is where people will know you authored it. "The year of publication may determine the length of the copyright term for a work made for hire or an anonymous or pseudonymous work." (US Coopyright Office). The year in the copyright notice is "The year of first publication of the work (or of creation if the work is unpublished)" (Same source).

@Faust76 agree with you except in cases where others would try to steal your work. I always register my work. Even though some would say it's unnecessary. Per your information here. It is precisely in agreement. Copyright registration usually can definitely occur before a work is published. Which is why a work can be copyrighted in 2017 and published im 2018.

@steve717 Well I mean, to stay on the topic of the question, it kinda depends on what is meant by "copyright year". If that refers to the copyright notice, as one would usually expect, then by law it's strictly the publication year; if one wants to backdate that then the only legal way is to make a limited publication, of possibly slightly different work, before. But a publishing house would likely not like that, as they want the prestige of first publication.

I'm no lawyer and not giving legal advice. In todays world you'd have to consider the laws of every country in the world, as there's no way the work could be restricted to, say, USA only.