This is a work of prodigious scholarship and imaginative synthesis. Mirowski sifted through a tremendous amount of historical material, and approached it with great creativity. He makes an excellent prima facie case that even late 20th Century neoclassical economics is based on an early form of 19th Century thermodynamics -- the way it was before formulation of the Second Law (the one about entropy).
I came at this with more background in physics than in economics (which isn't saying much). I found the history of the principle of the conservation of energy (Ch. 2) fascinating in its own right. For its concise treatment of that topic, this book deserves to be better-known in the "physics-physics" (as distinguished from econophysics) community. As for Prof. McCauley's comment in an earlier Amazon review that Mirowski is confusing potential energy with the action as the appropriate analogue to utility, my impression was that this error isn't unique to Mirowski, but was made by at least some of the economists whose work he is critiquing (e.g. Irving Fisher).
I give this four stars, though, because of some genuine weak points.
First, Mirowski spills much ink faulting economists because they use a physics metaphor that's outdated, but relatively little on the question of empirical justification (or lack thereof) for using any physics metaphor at all. More discussion of this point would have been helpful.
Second, Mirowski's discussion of physics is at times very tentative, like a student who copies stuff into a term paper without understanding it fully, but hoping that he can sort of fake his way through. E.g., he refers to the definition of a curl of a function as a condition (when the condition he means is that the curl = 0), and twice to an exact differential as an "exact differential equation" when no equation is stated; he throws around frequent references to the Lagrangian without ever mentioning its familiar form as the difference between kinetic and potential energy (T-V); and although he includes some equations in his discussion of general relativity, he neither explains his notation nor seems to be sure of what the equations represent.
Finally, his writing style is often pompous and overly ornate. In the early part of the book he seems to have been possessed by the spirits of the 18th and 19th Century writers he's discussing. (I was amazed to learn that he's a Baby Boomer who was still in his 30s when he wrote this book.) He adopts a more entertaining and sarcastic tone when he gets to the neoclassical economists, especially in his take on P. Samuelson near the end of the book. But too often he sounds like a too-clever college student. It makes for an unfortunate contrast to the depth and originality of his argument.