"She and old Marty were drinking Tom Collinses-in the middle of December, for God's sake."
Tom Collins
Creative Commons AttributionTom Collins - Credit: Lu, Flickr

That Holden, at sixteen, knows a Tom Collins is a summer drink, while the thirty-somethings from Seattle don't, gives readers an insight into Holden's wealthy and cultivated family background.  

Like a Gin Fizz, the main ingredients are gin, lemon juice and club soda.

Try a Tom Collins with this recipe.  Not in December, for God's sake.