I saved $160 by just reading this review/spoiler instead :)
As a former IR astronomer and author of several space mission proposals, I already knew some of the information in this book. But I still found it to be a fascinating window into the arcane and Byzantine process by which NASA produces complex scientific spacecraft. SIRTF/Spitzer took 20 years from announcement to launch, and it went through more fundamental changes in design and survived more NASA management fads than any spacecraft in history. Somehow Professor Rieke managed not to lose his sense of humor during this torture.
The impression one gets from reading this account is the whole system for selecting and funding NASA missions is fundamentally broken and needs to be totally overhauled. The amount of effort and money wasted on mission concepts that were abandoned is astonishing. Spitzer only worked because IR detector technology improved by a factor of 10,000 during its development cycle (mostly due to military-funded research).
I also was surprised at the number of dumb mistakes made by experienced engineers. The main contractor for the Spitzer instrument package was Ball Aerospace, who have a mixed reputation for competence. Clearly this mission was not one of their high points. Ball's pre-launch testing program seems to have caused more problems than it cured.
A lot of trouble was caused by defective components supplied by sub-contractors (which under the insane rules of the time could not be tested by the prime contractor or NASA). It seems incredible to me that after 40 years of building space probes, it is not possible to obtain basic parts like wiring harnesses and gas valves that aren't riddled with defects. There is no indication that the vendors of these defective parts were sued for damages, denied award fees, or placed on some NASA blacklist.
Everybody interested in space mission planning should read this book. You may laugh, you may cry, but you will learn a lot.