You never know, though. I recently found online some books by a couple of my favorite 1970s Russian science-fiction writers -- including one or two books I hadn't read and are not in my collection. But apparently the Moscow library somehow owns the copyright now...
I suspect the web site owner thinks he is doing something good by providing free copies of these works to whoever finds them, but many of these people who write these books count on the income from the sales of these books to keep themselves from being poor. Other authors count on the sales to finance ministries.
If they have permission to post or if the copyrights have run out, then I am more than happy to see these works on the internet. I suspect, however, that the website has not obtained permission. We shall see. I have e-mailed Walter Martin's web site and hopefully I will receive a response soon. If the copyright has been relinquished or permission has been granted, then I'd be more than happy to use Martin's work as fodder for some.... interesting threads.