reply to planet
"be aware that some pdf's require adobe acrobat reader, because of DRM."I assume this situation isn't too common, since I have been using a Mac since April, 2007 and have never encountered a pdf that Preview couldn't handle.
It's pretty common with eBooks checked from a public library --♬ Music is life ♬
Since I have never checked out or read an eBook, this probably explains why I haven't had any issues with Preview.