Think Tank by Dr. Madsen Pirie is something I recently read. A first hand account of the history of the Adam Smith Institute and its effect on government policy over the last 30 or so years. Some information I knew, some I did not and some of the accounts of meetings with government, especially in the early Blair years, were somewhat surprising. It's also quite straightforward and refreshingly frank.
I don't read many political books and I recommend even fewer but this one I do recommend and not just to fellow libertarians.