The South Ridge is the easiest and most popular of the three established routes on the Tower of Babel. Lopez describes it as a "top-ten scramble", but does not define what top ten. The actual Class 3 scrambling part of the climb is very enjoyable, but rather short. Most of the climb involves Class 2 travel over talus and boulders.
See the Getting There section of the main page for the approach to the general area.
The South Ridge Route begins at the col between the Tower of Babel and Mount Baal (unnamed on USGS topo - I have added the name to the topo here). This col can be reached without technical difficulty from the north or the south.
The preferred approach from the north is to attain the col between She Devil and Mount Baal (it can be reached directly from Sheep Lake via the obvious couloir), then traverse either over or around Mount Baal to the Baal - Babel col.
From the col between Mount Baal and the Tower of Babel, ascend the ridge to the north passing the first two obvious towers on the east (climber's right). After passing these towers, regain the ridge crest. When the next towers are reached, descend about 100 feet to the north side (climber's left) of the ridge. (Note that the third tower does not seem very large from the ridge crest and some false trails lead to the east. These quickly end at the top of very steep couloirs.) Stay as high as possible when traversing below the towers and head directly to what appears to be a dead end against a nearly vertical wall.
From the base of the wall, it is an easy scramble up to the right. Follow the obvious gully to the notch between the fourth tower and the main summit. This is the notch described elsewhere as the "Knife-Edge Notch". It is not really knife-edged, but it does provide a nice viewpoint down to Cannon Lake. This is where the fun Class 3 scrambling begins.
From the top of the small boulder leaning against the wall above, scramble up and to the climber's left toward a small free standing tower. From the tower, proceed up to and under an obvious overhang. This section is very steep and has some exposure, but there are many small ledges and with care, nothing harder than Class 3 need be climbed. Above this, it is an easy walk over talus to the summit.
Essential GearWhatever you normally carry for a day of scrambling in the mountains.
Some parties may wish to have a rope along for the more exposed Class 3 section above the notch, but experienced climbers and scramblers probably won't want one.