iBooks Author - iBooks Author, free from the Mac App store, allows you to create beautiful Multi-Touch textbooks — and just about any other kind of book.
Atavist - Atavist provides a suite of publishing tools to tell stories and build websites.
Ultimate eBook Creator - Ultimate eBook Creator is a dedicated eBook creator for creating the books for the Amazon Kindle.
My Ebook Maker - My Ebook Maker is a cloud-based system for creating eBooks that you can sell at any eBook store.
Liberio - If you want to enjoy the two basic features of creating and publishing eBooks, then Liberio will be suitable for that purpose that will deliver you both options on one platform.
Ebooks Writer - EBooksWriter is really a great program for creating eBooks of all type within few hours.