1. Ten Thousand Years of Solitude
This section was about the radioactive waste disposal in the Nevada salt flats. Benford was on one of the panels that gave an idea of how likely it was for people to stumble into it over a period of 10K years. He gave interesting process information and then the same for the second group (not his) that worked out what kind of marker would be used. There are many explanatory figures.
2. Vaults in Vacuum
This is about the proposed marker for the Cassini orbiter and Huygens lander. Again, he talks about the process not only in how to make a marker that could be read by far future beings, but in what would go on and how. There's a teeny bit of bitterness showing through that it never actually got on the spacecraft because the woman running the project insisted on taking all the credit and annoyed NASA. Again, lots of good figures.
3. The Library of Life
Benford talks about how we are killing species we don't even know we have on Earth and how we don't know if we can manage without all of them. He runs through a number of theories on how to save species -- both in vivo and in DNA or entire bodies. He strongly pushes a combination of in vivo sites with comprehensive frozen DNA.
4. Stewards of the Earth: The World as Message
This section is essentially about global warming. He brings up a lot of hypotheses about what could be done to stop it, to mediate it, or just letting it go. My biggest problem with this section was that the book was written 10 years ago and he was assuming the population would double in 50 years. That's possible, but the current estimate is only about 50% growth by then. So the timing and order of experiments and hypotheses wouldn't work the way he espouses. The general ideas, however, are very good.
I admit I enjoyed the two first sections more, probably because they were tech and not bio, but the book was very interesting. If you're interested in these subjects -- all how we talk to the future and in what ways -- you should read the book.