- Three editions: SE, CE, and CX
- SE and CE can run side-by-side via split-view multitasking
- Easily transfer books, themes, and scenes to SE or CE via SE's server
- Sync data among SE, CE editions running on iPad and iPhone
- Read DRM-free and password-free EPUB books in 3 book styles of your choice: Classic Book, Modern Book, Modern Scroll
- Choose or create your favorite themes with over 30 beautiful built-in day and night themes and Theme Editor
- Enhance book page layout on top of publisher's style with user's override over font, text layout control, page layout control, paragraph numbering, and more
- Look up words, translate sentences, mark pages, speak text, and mark text with notes
- Navigate across the pages conveniently in multiple ways with anchor button, two-level page slider, fast full-text search, and more
- Gesture control some common actions
- Import your favorite fonts
- Read also EPUB 3.0 books designed for vertical-writing and right-to-left languages
- Read DRM-free and password-free PDF books and papers
- Choose or create your favorite themes with over 20 beautiful built-in day themes and Theme Editor, and a white-on-black night theme
- Look up words, translate sentences, mark pages, speak text, and mark text with notes
- Navigate across the pages conveniently in multiple ways with anchor button, page-thumbnail slider, multi-page-icon view, and more
- Present the subset of browsable (visible) books using the bottom toolbar with 4 presentation styles and 13 sorting orders
- Choose the subset of browsable books using the top toolbar with a combination of (subject) tags, (book) sets, and keyword search (title, author, or series)
- Manage book sets with tools that give you user-defined book sets and more
- Manage tags with tools including the tag pool and more
- Modify individual book attributes (metadata or book info) including its cover image
- Enjoy a beautiful bookshelf in portrait or landscape orientation with built-in bookshelf background scenes, Scene Editor, and more
- Exchange is a multi-tabbed view where you can get your books in and out in many different ways
- Websites View is usually where you download from external book sources with built-in links to OPDS catalogs and HTML webpages, user-defined links, smart batch download, calibre support, Dropbox support, and more
- iTunes View enables file transfer via USB from and to your PC
- Queue View keeps track of files transferred from Websites or iTunes
- PC Upload View enables importing multiple files at a time from your PC via Wi-Fi
- Server View is where you can make your app act as a book server for other apps
- Mark notes that are overlappable and assigned with one of five levels of priority that are distinguishable independent of highlight colors of themes
- Edit a single note in Note Editor
- Manage multiple notes in Note List View and its companion, Library Notes View with user-defined note lists to keep track of different kinds of notes, that can be exported and shared
- Import a note file automatically as a new note list so as not to mingle with your existing notes
- Search notes by quotation or comment
- Enable web access to synced data via web browsers from desktop and mobile devices
- Sync data across your devices running SE, CE editions via secure cloud connection
- Sync reading positions, notes, vocab, and bookmarks of books
- Enable flexible resolution of potentially multiple reading positions from synced devices
- Guarantee deterministic sync results