Go back and read it again. Or watch the movie; both clearly include telepathic skills among the Bene Geseret and the Spacing Guild.
--Boris
Not quite, sorry. The Bene Gesserit often (probably, only the Reverend Mothers) have the "truthsaying" ability, but the implication is that they are able to pick up on very subtle body language/verbal cues to determine whether someone is telling the truth (due to their "prana-bindu" training, perhaps? It's been a while.) They can't even use telepathy with each other; instead, they've developed a subtle sign language and, probably, lip reading ability; why would they have needed sign language if they were telepathic? When they need to communicate with someone more directly/urgently and/or brainwash/control them, they use The Voice. But that's obviously vocal, not telepathic.
The Navigators of the Spacing Guild are mutated spice addicts, barely even human, whose use of the drug allows them to see through the fabric of space-time.
Neither ability can be accurately described as "telepathy".
In particular, if you got this impression from the film, it could be because David Lynch took the weird approach of having us hear all (or lots, anyway) of the characters' internal monologues from the book, overdubbed by all the actors in faux British accented whispers. But these were just internal monologues meant for the audience, not telepathy meant for the other characters.
On the other hand, later in the series (God Emperor) I do believe that Paul's son, Leto II "The Tyrant", has an ability more approaching telepathy. I forget what it was called, something like "second sight" or "other vision". He can "see" where people are and what they are doing, which helps him maintain control over his empire (and, which is the reason that, even later in the series, the invention of "no-ships" and "no-rooms" was necessary).
On the other hand I still don't think even Leto II could read minds or communicate telepathically. He had all those Duncan Idahos after all, half of whom would try to kill him, but he never knew exactly when....
(I should probably stop before I let loose some actual spoilers. Or reveal what a nerd I am :)