Well, that depends if you want to reinforce existing beliefs or challenge them with new ones.

After much reading from Smith to Marx to Keynes, it's my personal beliefs that the classical economists had it right and much of the 20th century thinking was wrong. To my mind, the experiences of the 20th century pretty much lay out that case, particularly with the twin a/b test of East/west Germany.

If you want a complete history of economic thought according to he Austrian school, then 'An Austrian Perspective on the History of Economic Thought' gives a thorough background from Ancient times to now on the evolution of economic thought and how people came up with the answers to puzzles like why is water essentially valueless as compared to gold when one is life and death and the other essentially useless. Going back deep into the original philosophers and coming forward helps to understand why thinking is the way it is.

The other book I recommend for people is 'The road to serfdom' by F.A. Hayek. This gives a thorough and as-yet unanswered critique as to why socialism in all its forms fails, and why it is an inherently unstable system that always leads to dictatorships and loss of wealth (hint: feature not bug) But these speak to my own beliefs which are decidedly no longer mainstream. Like many I studied this in undergraduate and masters courses but the explanations never really settled with me so I kept on reading. If you want to understand what the mainstream economic thinking is, just pick up a Krugmsn article and keep reading because most mainstream publications are wedded to the idea that governments can plan and manipulate economies into prosperity.