I lay awake and listen to the sounds of the night. The ringing in my ears – that constant single frequency. The sound that exists under it – a dull roar, like holding a seashell to your ear, only the report’s so low it’s almost inaudible. The hiss of air from my CPAP machine. My own shallow breathing. Sometimes I hear other things, like little footsteps charging over the roof. Possums. Well, it has to be. When I’m in my study, it’s not unusual to hear them leap onto the fence in the backyard. Or, sometimes, if I have friends over, when I escort them out late at night, we…