There's no perfect order for everyone. The trick is to spiral around revisiting levels and styles (and don't worry if you don't grok a part yet) until they all

There's no perfect order for everyone. The trick is to spiral around revisiting levels and styles (and don't worry if you don't grok a part yet) until they all start to gel and your brain forms aweb of connections. So many people think the second book they read on a topic is soooo much clearer than the first. But it doesn't much matter which book they dead first vs second :-)