Advanced users can tweak the EbookUI in settings to change font sizes and background colors. 2. Calibre Portable (The Powerhouse)
You can run them directly from a USB stick, external hard drive, or services like Dropbox. epub reader portable download
Unlike standard desktop apps, portable readers are "self-contained". Advanced users can tweak the EbookUI in settings
Supports EPUB, PDF, MOBI, CBZ, and CBR formats. external hard drive
Sumatra PDF is widely considered the fastest portable reader available.