Many wayward sleepers can combat sleeplessness with a set of sleepy-time behaviors we like to call "sleep hygiene."

But maybe the most important aspect of sleep hygiene is the need to create a restful sleep environment. Your bedroom should be dark, quiet and neither too warm nor too chilly. (60 to 65 degrees Fahrenheit works best for most people.)

This may seem like obvious advice, but environmental disturbances can disrupt sleep so subtly that the sleeper isn't even aware of the problem. For example, as morning light streams through your windows, it provides a powerful cue to the sleep/wake mechanism in your brain. As a result, you begin to wake much sooner than you want to. Over a period of days or weeks, this small loss of sleep can add up to a sizable sleep debt.

In the same way, noises and uncomfortable temperatures can slyly rob you of quality slumber. If you pay attention to these things and take steps to eliminate the intrusions — black-out drapes can keep the bedroom dark, for example, but may interfere with your ability to awaken on time, and a range of simple measures — double-paned windows, foam ear-plugs, sound-masking "white noise" machines, or even the steady drone of a fan — can be used to muffle annoying noise.

Once you have your sleep environment whipped into shape, it's time to focus on your mattress. After all, you spend a third of your life in bed; it's the most important piece of furniture you own. So in an upcoming dispatch, I'll visit the research-and-development labs of the Sealy mattress company in Cleveland, Ohio. There, I'll begin an ongoing investigation of the ins and outs of the mattress game. When I'm finished, you'll know all you need to know to buy and care for this crucial piece of slumber equipment.