InDesign CS5 is part of the Adobe Create Suite. According to the Adobe site it is page layout software that lets you design and preflight engaging page layouts for print or digital distribution with built-in creative tools and precise control over typography. Integrate interactivity, video, and audio for playback on tablets, smartphones, and computers.
It supports eBook authoring features to make the authoring task easier. It has tight integration with industry-leading Adobe software such as Adobe Photoshop®, Illustrator®, Acrobat®, and Flash® Professional enables highly productive workflows.
 InDesign 3
MobileRead thread - defines a method of using InDesign version CS3 to create ePub files.