Dever kept on writing the books up until about '94, '95, starting up a new series of skills and powers whenever the last ran out. So you've got the Kai books (which are old) then the Magnakai books (which are not as old) then the Grand Master books (late eighties, early 90s) and then the Grand Master New Order (mid-90s, when he finally realised that the market no longer existed for them...)
I also have a metric ton of Fighting Fantasy books lying around. Those are also quite cool, if not as complex.
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C. A. Monteath-Carr
One week until my GBA! Whoo!