My colleague here found a volume on Amazon titled,
"Essentials of RoboHelp," dated November 2007. She says it's geared
to RH 7. She's just getting into it; I haven't read it.
The three reviews are decidedly mixed. Judge for yourself.
She cautions against buying "RoboHelp for Dummies," which was
written for an earlier version of RH and is still available for
purchase.
I also see some guides written for RH 9, which newcomers
should understand was released years ago. You might call it RH 7's
granddaddy, from an earlier marriage on the other side of the
family.