This is for Skolian Empire fans and is a suggested read after THE MOON'S SHADOW, though anyone interested in the creative manifestations of higher physics would also find this a pleasurable read even if they've never experienced Asaro's style before. Style is the word for this book. Asaro's main character Dehya Selei, Ruby Pharaoh of the Skolian Empire is not only a Rhon telepath but also a brilliant mathematician. She can literally see mathematical formulae in Kyle space--that creative element in Asaro's fiction that enables instantaneous communication between the stars. Thus--if you've read THE RADIANT SEAS and remember the part where Prince Eldrin is captured by the Traders, then you also remember that at the same time Eldrin pushed his wife Dehya into the psiberweb. Everyone thought she was lost. This is the story of what happened to Dehya after the month she spent suspended in psiberspace.
Dehya coalesces on a distant world now isolated by the Radiance War and the fall of the Kyle Web. She has to survive another near capture by Traders, then make her way back to her own people where everyone is trying to pick up the pieces of a fractured society. Dehya uses mathematical probability to find the most important members of her scattered family, then begins to rebuild the Kyle Web and her empire. Some Skolians support her, others support the Assembly, so Dehya has to fight political battles as well as physical ones.
SPHERICAL HARMONIC overlaps THE RADIANT SEAS, ASCENDANT SUN, THE MOON'S SHADOW, and QUANTUM ROSE, though I did find that SPHERICAL HARMONIC doesn't dovetail chronologically with ASCENDANT SUN as well as it does with the others. No matter--even though it isn't a perfect story fit, SPHERICAL HARMONIC is an excellent work of art. There is beauty in the way Asaro turns mathematical ideas into words. You have to read it to believe it.