Did you download and read through the Kindle Publisher Guidelines pdf? You can get it on the KDP site at this very bookmarkable page (has all Amazon's free guides and utilities for publishing Kindle books):
http://www.amazon.com/gp/featu…..1000234621
Your question is answered in there.
Basically, you're supposed to add a "Start" entry in the final Guide section of the content.opf file (the "brains" of the epub, the file with the metadata, manifest, etc.) that tells the Kindle file where to begin… that is, what page should it open to by default, if you've never opened the book before. They recommend you specify the first page of real content, like the first page of Chapter 1, as opposed to, say, the copyright page. There is also a default menu item in a Kindle device and in Kindle software called Go To > Beginning, and the page that you set as the Start is also that Beginning page.
Here's an example from one of my Kindle projects, where we wanted the start of the book to be the Preface, which was its own HTML file named Preface.html:
<guide>
<reference href="cover.html" type="cover" title="Cover"/>
<reference type="toc" title="toc" href="toc.html" />
<reference type="start" title="Preface" href="Preface.html" />
</guide>
AM