Did you self-published the book you wrote? Did you use Pages for the page layout as well?
Apple Pages is a solid piece of software, do not get me wrong. In my testing, it performed better than all word processors for Mac, except for Mellel, which was the only serious contender. However, Word for Windows was still better.
My impression is that Pages is very much focused on page layout and lacks some word processing features that have been present in other software for years or even decades. It particularly frustrates me that Pages lacks cross-references, which is a feature that saves a lot of time and effort. And other features, such as indexing, are not there either.
I use Microsoft Word for Windows to create and edit some large documents. At this very moment, I am writing an article that is already 22,000 words long. Just before Christmas, I finished an 8,000-word long memorandum. And I have written at least three documents that are over 100,000 words long. All of them are packed with footnotes and cross-references. Word for Windows handles all of them with ease as if it were a walk in the park. Word for Mac can handle these documents as well, but it sometimes struggles in doing so. As for Pages, I am pretty sure it would be able to handle the documents well, but it would require me lots of extra effort as it lacks some features that are useful for me.
Sometimes I feel that addressing word processing and other office applications in a Mac environment is like bringing the elephant to the room. Many Mac users are picky about their hardware and software and are only happy with the very best they can find. I have seen some comparisons on how Adobe Photoshop performs on PCs and Macs. However, I have not found the same level of comparisons between Word and other Microsoft Office applications running on PCs and Macs. I think this is rather strange, because, as popular as Adobe Photoshop is, Microsoft Office is still the most widely used suite of applications in the whole world. Some Mac users just trash Microsoft Office for Mac, calling it "bloated", while praising the swiftness of Apple iWork applications. The elephant in the room is that Microsoft Office for Windows is fully-featured, fast, light, and stable, like nothing else available in the Mac environment. It is even more fully-featured than Microsoft Office for Mac, while also being faster and lighter than Apple iWork. And the fact is that not even the shiny new MacBook Pros, in all their glory and power, cannot run this software and have to deal with lesser alternatives, which is a blow to anyone wanting or needing to use office applications in a professional environment.