Hassig, in my opinion, is a meticulous and detailed scholar who studies his subjects from source documents and is very careful about what they actually say... and what they don't. Refusing to draw facile conclusions, and pointing out the fallacies of too broad an application of the universal theory he does rather a lot to enlighten one on the multitude of calendars of the mesoamerican world without trying to make them all the same. His balanced and thoughtful view make for a much better understanding of the subject.