I found myself really enjoying the Gorkon and crew, which I've never had any particular desire to read about before, so Ive since read the first three Gorkon novels, and am now on the fourth, where the series gets mysteriously retitled, just in time to end.
No mystery; it was decided that the title I.K.S. Gorkon might be too cryptic for new readers to know what it was about, and that Klingon Empire might be a better draw. Similar to why S.C.E. was changed to Corps of Engineers -- and, for that matter, why Enterprise was changed to Star Trek: Enterprise.