"I am writing a book about the Crusades so dull that I can scarcely write it"

This quote by Hilaire Belloc is an amusing way of revealing his disappointment with the tediousness of writing a book about the Crusades. He is suggesting that the subject matter is so dull that it is difficult to blog about. This could be due to the fact that the Crusades were a long and intricate series of wars that occurred over a period of centuries, making it challenging to condense into a single book. It might also be since the Crusades were a controversial topic, and Belloc may have been struggling to discover a method to provide the realities without taking sides. Whatever the factor, Belloc's quote is a funny way of revealing his aggravation with the problem of writing about the Crusades.