This route ascends the east face of the Thumb, taking a direttissima line to the north summit, following a prominent open-book weakness. Hill's guidebook (1993:161, 164) calls this line "5.7 or 5.8. Four (?) pitches". Also see Kline (1970:32). We climbed the route in four pitches of 30-40 m each, and found solid 5.8 cruxes on each pitch. One could probably get up in 3 pitches with a 60 m rope, though.
Start on the right face of the open book, following a stellar splitter crack system. Fun climbing takes you past some old fixed gear, including a pair of bolts at about 15-20 m (we didn't take a close look at these, because they were off to the left in the gully, so we couldn't tell if they were any good). At about 33 m, find another pair of newish bolts, and a fixed pin, at an awkward stance; belay here if you wish.
Continue up the back of the open book, past more fixed gear, through a short, fun, roof undercling. About halfway up the face (~70 m up), the "East Face Direct" route probably diverges off to the left (Hill 1993:161). Instead, follow the slightly rotten pillar to the right, up to the base of the huge gray dihedral above. The start of the chimney in this dihedral looks pretty loose, so, if need be, diverge slightly onto the right face for more solid, but airy and runout, climbing. After a while the chimney cleans up and narrows to an off-fist crack through a bulge; follow this line to a short blocky slope that leads to the summit ridge.

Approach as for Aviary Ort Overhangs. When that climbers' trail starts to head slightly right, cut left off the trail and climb low rock ledges uphill. The route starts at a huge pine/spruce tree with a sling. A sport route (Thundercracker?) ascends the short detached pillar about 30 feet right of the base of this climb.
Descend the standard 4th class route off the SE ridge.

Half set of nuts. Cams from thin fingers to #4 C4; we had doubles of fingers to hands, which was plenty adequate for our short pitches, and would probably work OK even if you ran the rope out more than we did.
Various pieces of old fixed gear pepper the lower half of the route. There is a good bolted anchor 33 m off the ground, but gear anchors will be necessary for every pitch above that point.