Einstein showed that postulating the aether was pointless, but his general relativity introduced a new structure to space and time. An quantum theory introduced more structure to the vacuum - a sea of filled energy states and virtual particles popping in and out of existence. Close goes on to show how this lead to the idea of the Higgs field which gives mass to elementary particles, and he looks at how everything began - could the big bang have arisen from a vacuum fluctuation?
There have been plenty of books about nothing. This one sticks to the point more than most, although sometimes I felt that it wasn't particularly inspiring. But other readers might disagree- it's a short, easy to read book, and if you are interested in some of the deep questions concerning the vacuum then you might well find it worth reading