Unless you are into chess engines the name Jeroen Noomen is likely unfamiliar, but the Dutch computer expert is a well-established engine opening book author. Since 1981 Noomen has been involved in computer chess as a writer in computer chess magazines and from 1990 to 1992 be developed opening books for programs like Mephisto Polgar, Mephisto MM IV, Mephisto RISC, as well as Rebel. He also authored opening books for Chess Tiger, Ruffian and Rybka. He is also an author of opening suites, a set of opening positions, intended for engine vs engine testing. For more information on this subject see Chessbase's article HERE.
From the spring of 2006 until the spring of 2009 he authored most of the Rybka opening books with the main goal of winning tournaments. When chess engines play each other recovering from a bad opening is almost impossible and his contribution resulted in thirteen clear first place finishes, including two ICGA world championships. In fact, during that time Rybka did not have a single bad opening position from among about 150 tournament games. Over time, Noomen, using Rybka 3, turned his attention more to public book releases that were deep and accurate.
Noomen took a break in 2009, but has recently returned to the opening book wars. He started his own blog in August and although it currently does not have many entries, it's worth a visit to get his latest book. The Rybka site also offers many of the Noomen downloads.
How to Make and Tune an Opening Book (ctg) in Chessbase at Chess2U...read article.
By the way, the Opening Tree from Chess Assistant is available online. The Opening Tree gives you statistics on all opening moves that are classified and stored in their opening database. You can also copy the moves in PGN line and paste it into any program. This Tree is very easy to use and the detailed stats can be very useful.