Before we export to ePub from InDesign, there are some import issues to understand. To get the best results for the ePub, we must be sure to provide appropriate tags for paragraph, character and object styles.
We do this through the 'Export Tagging' panel of each of the style dialogues. This is also where we decide how InDesign will split the ePub.
Fo our convenience we can set all of these together through the 'Edit all Export Tags Panel'.
Please NOTE: I no longer recommend the use of PDFXML Inspector from Adobe and this presentation covers the use of InDesign version CS5 not CS5.5 which has significant improvements in regard to ePUB export..
You may also want to watch the instructional screencast on the same subject.
If we source a public domain text on the web, such as those from the Gutenberg project, we may well find that each line of thext has a fixed length. This is because the text was probably scanned in and then converted to real text through OCR software. The text is laid out exactly as it was in the original source. This facsimile is not appropriate for our needs.