How much of Clausewitz's On War could be read in German or English? If you wanted to read Clausewitz's On War, it would be best to start reading it in your spare time at university. This book is a very profound literary work. You need to have a certain reading ability and cultural background to better understand the ideas and perspectives in it. Therefore, it is recommended to start reading from the simpler version and gradually increase the difficulty. Generally speaking, it was recommended to learn German first and read it after having a certain level of German. As for the English version of On War, it was recommended to learn English first and read it after having a certain foundation in English. Of course, if you already had a certain level of reading ability and cultural background, you could start reading both the German and English versions.