The title of his book stems from a comment made by Arthur Koestler that 'nobody read' Copernicus' great work that set the heliocentric system on a scientific basis. The wealth of marginalia compiled by Gingerich demonstrate otherwise.
I was amused to discover that for a brief period, there was a bit of rivalry between Gingerich and another scholar who was tracking down copies of De Rev: Bob Westman of UCSD, from whom I took a course on the history of science (including Copernicus and Galileo) when I was a wee freshman at UCLA.
In all, Gingerich locates over 600 copies of the first two editions, including copies owned by Maestlin, Kepler, Mercater and the future Saint Aloysius Gonzaga.
It's not known how many copies of each edition were initially printed, but a fair number have survived to the present day, despite the usual losses to WWII and theft. A more apt title for his book might be The Book Everybody Steals, since he recounts his involvement in the identification and recovery of several copies of the book that had been put up for auction after going missing from their home. For a first edition in an early binding, the pricetag is about $1 million. Because of the thefts, Gingerich is in the dubious position of having physically inspected more copies of the book than can now be located.
The appendix has a list of most of the extant copies, so you can locate the one closest to you. For me, I would have thought the copy at the Clark library, or the one at the UCLA Biomed Library (which has a ridiculous number of treasures in it) would be closest, but it turns out to be in the collection of Dr. Elliott Hinkes, who has his medical practice in Inglewood.
If you like books or if you like astronomy, you might look into The Book Nobody Read. If you like books and astronomy, it's a must.