About two and a half years ago I wrote a technical article on Medium.com, which included some graphs. I recently came across a book that was published (which I bought to see the content) last year that copied my words and graphics as-is. I was wondering whether this is legal, and who owns the rights (if anyone) to the content of my post.
According to the current version of the TOS:
You own the rights to the content you create and post on Medium.
By posting content to Medium, you give us a nonexclusive license to publish it on Medium Services, including anything reasonably related to publishing it (like storing, displaying, reformatting, and distributing it). In consideration for Medium granting you access to and use of the Services, you agree that Medium may enable advertising on the Services, including in connection with the display of your content or other information. We may also use your content to promote Medium, including its products and content. We will never sell your content to third parties without your explicit permission.
This explicitly says you own your content, although Medium has some rights to do some things. And they won't sell it without permission, so unless Medium itself is publishing this book, it would seem to be copyright infringement. (Of course, I don't know what the TOS said when you originally wrote the article.)
If what was copied was not copyrightable (like a quote from the Constitution, or a simple uncreative graph of something obvious) then it wouldn't be infringement. But your article was probably more than that.
Under US Law, you, as the original author, own the copyright to your post. Someone copying your post and publishing it in a book is a prima facie case of copyright infringement. The infringer could assert a fair use defense, where a court assesses the infringing use using a four factor test set forth in 17 U.S.C. 107, namely:
(1) the purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes;
(2) the nature of the copyrighted work;
(3) the amount and substantiality of the portion used in relation to the copyrighted work as a whole; and
(4) the effect of the use upon the potential market for or value of the copyrighted work.
How effective that defense would be is highly fact dependent and should be assessed by your attorney.
As for remedies, 17 U.S.C. 504 provides for statutory damages, which are damages that are unrelated to the profit the copyright holder would have made on the sales. The statutory damages range from $750-$30,000 per work and can be increased to as much as $150,000 in cases of wilful infringement. Furthermore, the statute, under section 505 also allows for a court to award attorney's fees in addition to the statutory damages. Based on the facts in your question, it sounds like the book publisher would be liable, meaning you have a defendant with deep pockets that could pay a judgement. You should retain an attorney to assert your rights against the publisher and author, jointly.