What is facinating is the way the author creates the historical context using a mixture of historical figures and people of his own imagination. We are given an insight to the caste system of ancient India and the stage is set for the Buddha's questions about suffering, it's origins, and his strong desire to put an end to suffering.
I'd say that this is appropriate for 9 year olds and up. For adults: my wife and I kept reading ahead. It is captivating. It has the air of an adventure story. I also enjoyed explaining and discussing the context of the story with my children.
Hope you enjoy it as much as we did.
Seriously, volume two carries on the dual track of intriguing characters who illustrate overarching themes, bringing them to life in a way that mere text almost never does. These are not scholarly books, by any means, but they depict the cultural milieu from which the Buddha and Buddhism arose. We haven't yet gotten to where Tezuka lets the Buddha expound the dharma, but, if he follows his established pattern, he's going to get things pretty straight.
I'm really looking forward to future volumes this series and think a whole range of others will soon be waiting with me.