Correct Michael, and that tool is a real gem (I have one), but expensive. For non-woodworkers, here is some info: a correctly set planer only ensures that the top and bottom of the piece being planed are 180 degrees to each other, or "on the same plane". If you started out with a parallelogram (or something close), after planing all 4 sides you will still have a parallelogram. To straighten up a piece, here is how to do it: plane 2 opposing sides, then go to an accurately set table saw(the blade is 90 degree to the saw surface), put either one of the 2 sides just planned "down", so that it rests on the table saw surface, and keeping downward pressure on that planned side, rip a 90 degree angle to either of the planned sides, then take the side you just ripped and turn it "down" to the bottom, and then plane the top side to that. You should now have four 90 degree angles.
A jointer is "easier" and more accurate to get true 90 degree angles if you know what you are doing, but there is a learning curve that not many master. Hope this helops someone, cheers.
Edited: I forgot to mention that there are speciality router bits that will cut a 90 degree angle and be very accurate if you can solve the vibration problem.
Edited again: both planer and jointer give far smoother cut/surface than a saw blade ever will, even with blade stabilizers.