As Cambridge professor John Ray writes in The Rosetta Stone, the fractured granite slab "gave us back one of the longest and most romantic chapters of our history, a chapter which had been thought lost beyond recall." Ray's brief book evokes the process of rediscovery, succinctly capturing the story of the stone's recovery and decipherment and passionately, albeit unoriginally, arguing for the slab's iconic status.
Like Ptolemy V, the Rosetta Stone is of accidental significance. One of many stelae -- stone markers -- produced as political propaganda in the year 196 B.C., it advertised the pharaoh's generosity to three key constituencies -- the Greek government, the Egyptian people and the otherworldly gods -- each of whom used a different script. The gods happened to read hieroglyphics.
Haven't read it so I won't comment. I like this bit though: Pre-Rosetta Egyptology, on the other hand, was mired in enigma, operating under the assumption that the land of pharaohs was a "nation of philosophers and religious visionaries [who] codified their profoundest insights into the symbols on their obelisks and temples."
Which is similar to how the Maya were held before the script began to be deciphered. David Drew goes into this in his book The Lost Chronicles of the Maya Kings as well in the Maya case. IIRC, there was a single stone at one site (I'll look it up when I get home tonight) that had 7-8 figures carved into it on all sides and was initially interpreted as a group of philosopher-kings having a conference to work out whatever profound astronomical issues of the day they had. Turned out it was commissioned by one king to show his ancestral line of former kings, thus solidifying his claim to the throne.