Picked this up because I saw the anime, and that's basically what the book is: a shounen anime / manga in novel form. It's an action-packed, fast-paced story set in post-apocalyptic Japan, about a Mushroom Keeper and his encounter with a doctor who becomes his adventuring partner. This first volume covers their attempt to find Rust-Eater mushrooms, which has the ability to cure people from the Rust that's been plaguing the land. It ends in a really nice note despite having a lot more volumes to come, promising more exciting adventures for Bisco and Milo.
That being said, I had to knock off a star despite enjoying the book... because of how sexist it can be at times. Particularly when it comes to Pawoo, since the writing keeps pointing out about how it's such a waste that a woman as beautiful as her enjoys being a fierce warrior when she should be getting married. I understand that Japan does view women that way, but I just can't bring myself to like it.
Aside from that, this is the start of a really promising series. Will definitely be picking up the next book.