The short answer is yes. While Röhl’s monumental biography is a doorstopper of a book, it is the culmination of years of research by a major figure among historians of Germany. It is very likely that this multivolume biography will be a benchmark text for Wilhelmine scholars in the next decades.

However, this does not mean that Röhl’s biography is gospel or the definitive last word on the subject. Röhl himself is an important figure within German historiography and he was one of the first English-language historians to expand upon the pioneering and controversial work of Fritz Fischer. Clark's somewhat negative review is reflective of the fact that Röhl’s dim assessment of the Kaiserreich and its leader is somewhat passe in historical circles today. Although there is some evidence that the current generation of German historians writing today is going back to this negative interpretation, the contemporary English-language historiography tends to draw a more nuanced picture of this period in German history. For example, while historians today accept much of the evidence Fischer presented, most mainstream scholarship (again, leaving out the current German-language works) tends to reject his overall thesis. Moreover, one of the more common critiques of both Fischer and Röhl are that they tend to focus so heavily on the German side of the equation of issues like the slide to war that they ignore or sideline the pan-European context. For example, Dominic Lieven has written a recent history of Imperial Russia's wartime experience, The End of Tsarist Russia, and in it he reasserts an earlier contention that Berlin was responsible for the outbreak of the war, but that such responsibility meant very little as the tsarist state was in such a parlous political condition post-1905 that many tsarist officials perceived evading war as far more politically dangerous than fighting one.

So Röhl is definitely worth the time invested in it, especially for his picture of the German domestic scene. Butt be aware that Röhl does interpret German foreign policy through Fischer's somewhat outdated concept of Weltmacht.