Yesterday I was looking for some information on early Praktica models and stumbled upon the pentax-slr.com website. How I've not come across this Norwegian site before is a mystery, considering the amount of time I've spent researching our old cameras, but that's very much the charm of the internet. As well as the site's very comprehensive coverage of most things Pentax, this forms only a small portion of the vast range of other brands and manufacturers, usually arranged in timeline fashion. Great reading and a very useful resource, with concise text and excellent illustrations. Frontpage - www.pentax-slr.com
Thanks rick, I had missed it too. of course, for another look at some other M42 mount there's still Dr. Mike's: Mike's Praktica Collection