Now, this is not to cast aspersions on Dr. Thorne's prose, or the interest level of his subjects, just noting that this was not exactly a speedy "page turner" ... I often envy fiction readers their easy tasks, but figure that life is too short not to read serious books (if I want fantasy, I have the SciFi channel!).
Frankly, I'm guessing that this must be used as a college text, as it appears in a lot more users' libraries on L.T. than many more accessible physics books. It is an interesting and ambitious venture ... starting off with Einstein's work and showing how those various theories were developed upon over the years, with particular emphasis on the evolution of the concept of "black holes" and various radio sources. One of the ongoing efforts Thorne makes in the book is to try to give a "visual sense" of assorted 4-D concepts, charted out in 2-D representations of 3-D models ... a challenge with the simplest diagrams, and nearly impossible for some of the more convoluted versions of curved space/time! Thorne puts a lot of the theory in context by way of "fleshing out" the scientists responsible for the concepts. He especially provides an interesting sketch of Soviet science in its somewhat-parallel development during the Cold War.
There were several fascinating bits in Black Holes and Time Warps that I had either not encountered or at least not registered previously, such as that all sub-atomic particles share the same sort of wave/particle dual nature that is more commonly known for the photon, plus there are some very interesting, almost "fractal" recurrences of sets of physical laws (like classical thermodynamics) in completely unexpected theoretical settings. This also whetted my appetite for more info on the Planck-Wheeler length, area, and time ... an amazing set of concepts/equations that brings reality down to the smallest possible gauges (at 10-33cm, where "space has become a froth of probabilistic quantum foam").
Now, this is yet another of those physics books that I've had sitting around for ages, having come out in 1994 ... so a lot of the "raw cutting edge" bits in here have likely been eclipsed by other research, and there are, no doubt, many answers for stuff left hanging in this. However, unlike some of the other older physics books I've read recently, this doesn't feel as dated ... probably because Thorne was operating in a specialization which wasn't waiting for the SSC to come on line.
There is a paperback version of this that is still in print, so you should be able to find it locally. Amazingly (for such an obscure topic), there aren't any "dirt cheap" copies out there, but you could get a "very good" copy for about half of what Amazon's charging for a new one (which also makes me think these are in the textbook market). It is fascinating stuff, if you're into physics, and there's info in this that I've not found elsewhere, so could well be worth your while.
*Although this particular pattern is breaking in that my next book in "that slot" is a hefty large-format book on Tibetan art that I bought back in '91 when I was in NYC for the Kalachakra.