Not a lot to say here -- you really have to check it out for yourself. But let this quotation from the first in the series set the scene about the importance of signage on human behavior and emotion:
"Signage—the kind we see on city streets, in airports, on highways, in hospital corridors—is the most useful thing we pay no attention to. When it works well, it tells us where we are... and it helps us to get where we want to go (as when an airport banner directs us to our gate). When it fails, we miss trains, we're late to appointments, we spend hours pacing the indistinguishable floors of underground parking garages, muttering to ourselves in mounting frustration and fury."
SIGNS: HOW THEY TELL US WHERE TO GO
Slate series by Julia Turner, March 2010
Part I. The Secret Language of Signs
They're the most useful thing you pay no attention to. Start paying attention.
Part II. Lost in Penn Station
Why are the signs at the nation's busiest train hub so confusing?
Part III. Legible London
Can better signs help people understand an extremely disorienting city?
Part IV. Do You Draw Good Maps?
A professor has been examining hand-drawn maps for three decades. Send him yours.
Part V. The Big Red Word vs. the Little Green Man
The international war over exit signs.
Part VI. A World Without Signs
Does the advent of GPS mean we'll no longer need them?