First and foremost, it is a book geared towards fish aquarists. And it is a heavy read with alot of chemistry and biology. To sum up the book: the author wrote the book to bring it to the reader's attention that an aquarium is a sort of (semi)closed ecosystem, and it needs to be thought of as this in order to be successful in raising the plants and animals inside the aquarium. she then describes the biological principles behind her methods of setting up and maintaining "low-tech" planted aquariums (as opposed to hi-tech, like those of takashi amano). She uses.