This book, in four volumes, is quite a remarkable achievement. Volume 1 is an introductory essay that is the first thing that anyone interested in this text should read. It is quite brilliant. It has been reissued by Oxford:Clarendon and seems also to be available on-line (http://archive.org/details/politicsofarist01arisuoft)
This is what the reprint looks like:
And that is the cover picture that GR should probably be using.