It's obvious that you put a lot of work into this map, but I hope you won't feel put down when I say: it isn't very good.

Where to start...

First, the style: you said that this is meant for a book. What for, exactly? To help you gather your thoughts and keep track of your heroes movement? Or a map to show to your readers?
In the first case, it really doesn't matter what the map looks like, as long as you are happy with it. But in the second case, you should rather use a style that can be printed in a book, especially in black and white.

Next, the layout: Are you set on this world? Is this how you picture it in your mind... or could you change it? If you can, I would advise you to start over again. You current layout suffers from what I like to call the "fill in the blanks" syndrom: you have a rectangular piece of paper, and try to fill it with "geography". This way quite often results in very rectangular landscape.
Do you need all this stuff? Again, you said it is for a book. Do you visit all those island in the book? Perhaps you should rather put your focus on where most of your story happens. It keeps you from having to fill in the "whole world" (on a rectangular piece of paper )

Next, the geography: most obvious flaw are your various rivers. Usually, rivers don't behave as you show them on your map (wierd magical stuff happening not included). A good start on this topic is this thread.


I hope I didn't disencourage you too much with all that. Just keep going... not many people get it all correct in the first attempt!