Main author might want to exclude me from the list of authors About a year ago, a foreign researcher invited me to co-author a review paper with him. He had already a 50 page long draft that needed editing and improving. After I was done with it (literature review, re-writing big parts of the text, adding big parts to the text, enlarging the bibliography) the paper was 70 pages long; submitted, accepted, in press. So far so good.

A few months later, he invited me to co-author a follow-up review, to which I happily agreed. This  time his draft was of a poorer quality, so in fact I re-wrote it from scratch, using the first version as a skeleton or table of contents.

After I finished and sent him the paper, he stopped responding to my e-mails since several weeks (I don't know him personally). I fear he might want to submit the paper without including me as co-author (it's a justified fear, but I'll refrain from describing the details of our collaboration).

What can I do if this will indeed happen? In its current form, the paper is partially my intellectual property, and I don't allow to publish it without me. I have all the source files and e-mails regarding this work. Could I write to the publisher explaining the situation and demand to withdraw the paper?
If he's stopped responding to your emails and you don't know him personally, it could be very difficult for you to figure out where and when he may submit this paper, and without that information, you can't contact the publisher to explain your position. It may be wise to maintain records (ideally timestamped) of your email correspondence with him, and of your version of the paper.

If you have these artifacts saved, and you later see the paper without your name attached in a journal somewhere, then you can contact the publisher to explain the situation, and provide your timestamped records as evidence that the paper contains your intellectual property.

I would recommend continuing to try and contact the professor. If you're very concerned about them publishing without your name, you could email him and ask that if he publishes the paper, not to use the version you wrote, and not to attach your name to it (save any and all of this correspondence). In this case, you would lose the opportunity to be published, but you would also retain your intellectual property and refrain from having your name put on a paper published without your knowledge.