My main focus of study is Prussian/early German history. I recently brought 2 books by Christopher Clark: Iron Kingdom: The Rise and Fall of Prussia:1600-1947 and The Sleepwalkers: How Europe Went to War in 1914 and was looking at another book that happened to be written by him as well on Kaiser Willhelm II...
My question is if he is a historiographically trustworthy author, and if there is any advice I should take in to account while reading his books. I have been taught to not load up on one author for any singular subject and to get multiple sources from different time periods/views...
Yes he is a totally solid author but that's also good advice to get many different viewpoints. His book Sleepwalkers is introductory at best though w.r.t. WW1 but his book on Prussia is probably the best non-textbook related work out there I've found.