Why is a paperback novel like a hat?

There's got to be a funny punchline here...and someone will post it for me, I hope. However, that goofy question really does have a point. Which, naturally, I'm going to get to - after meandering around it a bit.

Last month I took a train trip along the Northeast Corridor, and since it is now winter (yes, that's what the calendar says), I donned what I felt was a whimsical tribute to the days of