We strongly recommend you use InDesign for preparing your book for print, for it allows you to work well with both art and text and does a great job of ensuring proper PDF/X-1a:2001 output.
We understand that InDesign is expensive, however, so you might consider Scribus (a free layout program) for getting started.
We suggest you do not use Microsoft Word to lay out your books; MS Word will not allow you to select any actual ink for the text color, so you will not have an easy time getting your ink coverage right. Further, you won't be able to export as PDF/X-1a:2001.
Photoshop and Illustrator are fantastic for manipulating art, controlling the ink coverage and, used in tandem with InDesign, will get you high-quality results.