title_body: EPUB Page number values According to the epub spec a page number can be defined as:
  
  &lt;p&gt;
     …
     &lt;span epub:type="pagebreak" id="page23"&gt;23&lt;/span&gt;
     …
  &lt;/p&gt;
  
  
  And in the page-list:
  
  &lt;nav epub:type="page-list"&gt;
    &lt;ol&gt;
      …
      &lt;li&gt;&lt;a href="georgia.xhtml#page752"&gt;752&lt;/a&gt;&lt;/li&gt;
      …
    &lt;/ol&gt;
  &lt;/nav&gt;
  
  
  Does the value of the page number need to be a integer value? In otherwords, will the following be valid:
  
  &lt;p&gt;
     …
     &lt;span epub:type="pagebreak" id="pagei"&gt;i&lt;/span&gt;
     …
  &lt;/p&gt;
  
  
  Will this cause issues on any of the popular readers?
upvoted_answer: Support for actual page numbers is practically non-existent on almost all e-readers. You've tagged this epub3—I'll point out that epub3 support is also practically non-existent...
  
  I don't think using non-integer values is going to cause issues on many readers, because I doubt many of them will care. I also don't think many of them will break on the page, unless you have explicit css to force a page break.