Mastering the Sicilian Defense has been published by Chrysalis Publishers.  This is Danny Kopec's comprehensive survey of the most popular defense in the e4 repertoire.

Mastering Chess has been rereleased Dover Publications.  Edited by International Master Dr. Danny Kopec, with contributions by GM Nigel Davies, Geoff Chandler, Chris Morrison, and the late Ian Mullen. Covers Tactics and Combinations, How to Analyze a Position, Positional Structures, Opening Principles and Ideas, and Essential Endings. Exercises accompany each Chapter. There are also practical tournament tips by Ian Mullen. The book can be beneficial and enjoyable to people at all levels and ages, from youngster to senior, from novice through expert.

For over 20 years, this book has been rated one of the Top Five General Instructional Chess Books. Don't miss your last chance to get your autographed copy of the new version of this ground-breaking book!

Practical Middlegame Techniques has been published by Cadogan (1997).  This is Danny Kopec and Rudy Blumenfeld's analysis of these techniques.

A limited number of copies are now available for only $20!!!

I have just purchased 3 of your DVDs on pawn structure. I am very very pleased to own these DVDs. I enjoy your down to earth style of explaining things. I have found that...I not only am remembering more, but I have time to think about what you have said with out having to stop the DVD. I can't wait to buy your DVD on analyzing positions. Thank you so much for making so much information so affordable. This is just what my game needs.
-Francis Thomas Laity

I recently purchased the complete set of 8 DVD's...and have been enjoying learning from all the material you present on them. I find your approach easy to follow and I know that... with time and continuing study I'll "get" more and more of it.... It seems that already my "intuition" about what moves might be up-coming is improving and that I'm retaining more as well. Anyway, I thank you for all the effort you've put into helping others play better and enjoy chess more deeply and look forward to working with your new material as it becomes available.
-John M., South Portland, Maine

Your products are great. - I've learned a lot aready.
-Harry J., Lancaster, PA

"International Master Dr. Danny Kopec possesses two unique qualities of great value to all aspiring chess players, his awesome understanding of endgame technique and an innate creativity for sacrificial combinations. The art of endgames and sacrifices can catapult any player up the ratings lists."
-Nicholas C., Midlothian, VA

I have just finished viewing the DVD's you sent me (7 in total), and although I have a reasonable understanding of chess priciples and have a internet chess rating of 2000+, I definately picked up some tips, especially in your pawn DVD's... I knew my pawn play was lacking in quality, your DVD's confirmed that.
I have just recently purchased your book Mastering The Sicilian and found it to be a excellent book for understanding ideas -positional and tactical in the Sicilian.
-Paul D., Perth, Western Australia