In short: a number of essays where deGrasse Tyson argues that America needs to spend more on NASA and its science and research. Many good arguments that people might not be thinking about. Some history on space travels and their impacts on science, culture, and more. He goes on arguing that America needs more space travels, but he's arguing that while space travels without humans (only robots) is cheaper, astronauts become symbols, almost celebrities and can cause the general population to take a greater interest in space travels, something robots won't.
All in all, the arguments are all well and good, but with the endless repetition that comes out of the fact that this is just a collection of essays, many are repeated (often the ones with least impact), and they lose their "punch" after the third time they're are repeated.