E-book management without installation.
Download Portable Calibre 32-64 bit Online (0.3 MB) 27/02/16
In first screen enter: 2.54.0 (or 1.48.0 for Windows XP)
Online installer is also setup extractor if expected win32 and/or win64 .msi is found in its folder.
Extract and run CalibrePortable.
Default Library in CalibrePortable, edit CalibrePortable.ini to change (must be in same drive).
Settings of installed Calibre should be preserved.