Others told me that this book was disappointing when compared to The Kite Runner and A Thousand Splendid Suns. It's been a while since I read those so it is hard for me to compare, but I really enjoyed this book.
It starts with exploring the special bond between 10 year old Abdullah and his 3 year old sister Pari. They are inseparable - it is as if Abdullah has raised her. But, they are suddenly separated and the rest of the book explores this loss. For Abdullah it is direct - he is never quite whole. For Pari, more indirect as she eventually forgets about Abdullah though she lives most of her life knowing something is missing but unsure what.
We also learn more about the life of the children's uncle Nabi who at first seems cruel but as he ages we see the kinder, more devoted side of him. And it is he, who following his death, reveals the information necessary to try to reunite the young siblings. His illicit relationship with his employers is also of interest.
There are several other side stories - some more interesting and tied to the main story than others. Nabi's sisters (one of whom is the step mother of Abdullah and Pari) are very interesting - and we really follow them from childhood to death. The stories of the Greek doctor who comes to live with Nabi and his family and friend in Greece are really more tangential and the parts in Greece seem particularly unnecessary as does the story of two cousins who live down the street from Nabi. It also seemed a little unnecessary to relate the story of Abdullah's younger half brother though I suppose it was illustrative of the problems that arose in Afghanistan following the various invasions when former Afghans returned to their homes from refugee camps in Pakistan.
As with Hosseini's other books, we also follow the changes to Afghanistan - from a relatively free society in the 50s, through the Russian invasion, the Taliban era and the US invasion. And of course al of these changes create painful and dangerous circumstances for the characters.
So, at times the book was disjointed due to all the story lines but in all I did enjoy reading it.