A book of this sort is totally impossible to tell from a normal one, although if a detect magic spell is cast, there will be a magical aura noted. 

Any character who opens the work and reads so much as a single glyph therein must make 2 saving throws versus magic. 

The first is to determine if 1 point of Intelligence is lost or not, the second is to find if 2 points of Wisdom are lost. 

Once opened and read, the vacuous grimoire remains, and it must be burned to be rid of it after first casting a remove curse spell. 

If the tome is placed with other books, its appearance will instantly alter to conform to one of the other works it is amongst.