It is an excellent biography that surprisingly has some new insights into the life of Philip II that Parker had done so much to illuminate in his prior books. Parker actually managed to get access to some new archival material that was cataloged in 2012. It does not radically alter the tenets of Parker's previous books on Phillip II, but the Imprudent King focuses a tad more on Philip's earlier life and less on the Armada, which he covered in The Grand Strategy of Philip II. Two things Parker does really well is explain the geostrategic context of the sixteenth century and be very judicious about exploring the mentalities of the various actors. I find Parker as a whole to be a much better biographer than Henry Kamen both in terms of readability and Parker's more critical approach to Philip II.

This book is fantastic. I would say it is among Parker's best work. If you have read and enjoyed The Grand Strategy of Philip II, I highly recommend this book. If you ever wonder at all why the Spanish empire seemed to have fumbled so badly all the time, you owe it to yourself to read this, and in addition read through his older paper:

G. Parker, "Why Did the Dutch Revolt Last Eighty Years?," Trans. Royal Historical Society, vol. 26, December 1976.

That paper is perhaps the best concise explanation of not only the Dutch Revolt, but also what concerns truly occupied Charles V, Philip II, Philip III, and Philip IV, and whether those concerns were justified. I think that this latest book is written more in the spirit of that paper, rather than The Grand Strategy, due to its larger context.

I remember you had asked about Kamen before. Pay attention to the Preface in Parker's latest book, as it puts Kamen in the correct perspective, which Parker calls "severe determinism." As a person trained in the hard sciences, this is one factor that consistently bothers me when I read Kamen's books. Parker is much more disciplined in his research.