Wow!  This book is not my usual lighthearted romance; it's intense -- and great!  If I were looking for intense, I would probably have given it 5 stars, as both the drama of the plot and the romance moved my emotions more deeply than most anything I've read.  Just superb!  Re my personal preferences, I found myself worrying too much for the characters to fully relax and enjoy myself (also I found some of the history was laid in a little heavy here and there, and I didn't love the resolution with the villain) -- thus the 4 stars.