Lulu has withdrawn Ulwencreutz's Royal Families in Europe, according to Paul Theroff, who filed a complaint against the publisher, citing evidence that the book was taken straight from his website, An Online Gotha. Mr. Ulwencreutz claimed he paid researchers to do the work, and was unaware of the similiarities between his book and An Online Gotha.
Here in the United States, ignorance is no excuse of the law. Editors and publishers are responsible for their products, including making sure no intellectual property laws were violated.
Since 1978, here in the USA (and other countries' laws are similar), one does not need to state that their work is copyrighted. It is automatic. This was further defined by the more recent Digital Millennium Copyright Act.
The Internet and Public Domain do not mean the same thing.