From Howard Marks’ latest quarterly letter The Outlook for Equities.  Looks like someone posted the full letter here.  It’s only nine pages and worth your time.

Bull Market Stages

1. When a few forward-looking people begin to believe things will get better
2. When most investors realize improvement is actually underway, and
3. When everyone’s sure things will get better forever

Bear Market Stages

1. When a few prudent investors recognize that, despite the prevailing bullishness, things won’t always be rosy
2. When most investors recognize things are deteriorating, and
3. When everyone’s convinced things can only get worse

As for where we’re at today (in US Equities) he thinks we’re somewhere in the first half of stage two of a bull market – pessimists no longer control market prices, but certainly neither have carefree optimists taken over.