content: In 1999, when this was published, there was not much high-quality online material of this type. Now there is lots, including Wikipedia. I purchased this to read the overview papers, which I found elementary and pedagogical---not useful for research. I read a sampling of entries and found them fragmented and rather elementary. Thus, this book (like many other 'encyclopedia' type books, are superannuated. I will donate my copy to charity.