Some plants are listed more than once because they fit into more than one category. Each time the plant is listed it includes a very short description and water, light and feeding information. I use this book mostly for the pictures and the placement ideas. It has great pictures and great ideas for placement.
The room to room guide is something I haven't found in any other book. It gives you an idea of what plant to put in what room. Do you have a room with a sunny windowsill? The Locations will give you some suggestions for your windowsill. If you have a dry room, this book has suggestions. It has suggestions for almost every room in the house. This book is good for beginners and intermediate plant grower. The advanced plant grower might not find it as helpful, but the advance grower might still find the Locations section interesting.
This book is definately for someone with little gardening experience. I found it to be extremely helpful.
Based on the info in this book I purchased a large hibiscus plant for a sunny sliding glass door window. It's gorgeous, it's blooming -- it's all I could want in a plant.
The book IS organized -- and it's true, the same plant appears in several places, but that's because a low-light plant might also be a good trailing plant! The organization is by type of foliage, light requirements, showiness of the plant, and other categories. Probably not the kind of classification that a horticulturist would like, but it was very useful to me. There are lots of pictures so you see exactly what the plant will look like, and they're labeled with both Latin and common names.
If you're looking for a plant for a specific place in your house, this book is an excellent resource.