Try removing the leading "881256329.epub" from the paths in the linked ZIP to create a (potentially) valid EPUB. If you still have problems after pruning the le

Try removing the leading "881256329.epub" from the paths in the linked ZIP to create a (potentially) valid EPUB. If you still have problems after pruning the leading directory, you might also try a ZIP utility that doesn't create an extra __MACOSX directory in the ZIP file to store OS X-specific metadata. In particular, I can confirm that the file created by running zip -rqX ~/path/to/Swift.epub . from within ~/Library/Containers/com.apple.BKAgentService/Data/Documents/iBooks/Books/881256329.epub after downloading on OS X iBooks works fine without conversion in Google Play Books on Android 4.4.