The book starts with an accident leading to scientific proof that psychic powers exist, allowing for the former "freaks" of the world to come out into the open. Anyone familiar with this author will not be surprised to hear the book contains all the excitement you might expect from Anne McCaffrey writing about people with "super powers".
However, this is no shallow tale of caped crusaders fighting all evil, but instead an intelligent look at the responsibilities of (for example) precognition and the effects such people could have on mankind. As so often, Ms McCaffrey uses a "Sci-fi" theme but in such a natural way that the people appear human so you can empathise with them.
A brilliant read and a brilliant series. Just breeze through from start to finish and lose yourself for a while, or spend more time considering the ideas suggested - either way you're almost guaranteed a great time.