Copyright from 1979 and out of print.

When a company goes out of business they usually transfer ownership of any copyrights or patents. The business should have filed paperwork with the state that they were incorporated in identifying the disposition of their assets.

You'd have to figure out which state they were incorporated through and file a request for a copy of the disposition (it should be a public record but there may be a minor fee for photocopying, etc..).

If you wanted to copyright for yourself you'd have to contact whomever the current holder is and offer to buy it from them.

I discovered that this company also let all of it's trademarks expire in 1979. I don't think that they transferred the copyrights to any other company because a google search on the material and trademark names only brings up their company name, and nobody else.

The results that come up are just a bunch of people selling their old collection of literature on eBay.

I guess the best thing for me to do would be to check with a lawyer to see if I can obtain the rights legally and within my budget.

Trademarks and copyrights are two entirely different beasts. Trademarks are "use it or lose it" types of intellectual property, whereas copyrights persist even if no one bothers with them for decades. A copyright that was in existence in 1979 was probably copyrighted under the old statute, so it may have lapsed by now. But there is a very good chance that it was extended by law, so it may still be valid (the copyright law underwent two major revisions in 1978 and 1992, so things get very complicated around that time). Your best bet is to talk with a lawyer.