There are three phases of tourism: discovery, promotion, and crowd control. These phases also apply to climbing areas.
Beckey's guide has documented the discovery phase in the Cascades. For climbers interested in new routes, Beckey's guide remains essential. It's also a good idea to browse the American Alpine Journal for routes put up since Beckey's last edition was published (although Journal entries for the Cascades have been pretty scarce the past few years).
Nelson's and Potterfield's guides are a sign that phase two has arrived in the Cascades--promotion. In a big range like this, climbers want to do the classics, and selected-route books lead them right there (or, at least, to one person's list).
As Forrest said, explorers aren't hampered by selected-route books. New climbers love them. My concern (as you've probably guessed) is what happens when we enter phase three--crowd control. In some places in the North Cascades like Boston Basin we're already there. One solution is to try and spread the climbers out. Voila! More selected route books!
I don't know where this will all lead. I'm sure that Nelson, Potterfield and The Mountaineers Books are at least aware of these issues. Notice how routes in "Fifty Classic Climbs" have been omitted from both their volumes. This is partly just a marketing decision, but also an acknowledgement that some classics don't need more attention.
Lowell Skoog
lowell.skoog@alpenglow.org