The next major edit -- 0.3 is in progress. Changes expected: revision control of the document, explanation of why 'unit of account' is bad terminology -- it needs to be redefined away from a generalized term to address permissions and UTXOs. It is more accurately an 'implicit unit of account' in contrast to the traditional explicit.
Here is the most current copy of the paper (0.2): Digital Currencies in Practice by Alex Waters
Another great talk that gives a collegial narrative on the current Bitcoin block size debate:
Gavin Andresen, Adam Back, and Trace Mayer Discuss Bitcoin Block Size
Nick Szabo on Let's Talk Bitcoin
Nick's statements re: typical bitcoin jargon ("trust-less", decentralization, governance, etc.) are so important for the Bitcoin community to hear. His description of trust, identity, governance, consensus, etc. are awesome. I would say this is the best Bitcoin interview in 2015.