1 Insomnia is underappreciated. 2 Many people would rather admit to their fetishes and contagious rashes than confess to insomnia. Insomnia is not merely a condition, at least not in our culture. It is a disorder. Insomnia is proof that you are not calm of mind, clear of conscience, at peace in your body. 'Insomniac' sounds suspiciously like 'maniac.' 3 Anywhere you turn these days there's someone counseling us on how to avoid the insomnia plague, which, we're warned, can be caused by pizza, Scotch, depression, work, love, arthritis, coffee, red wails, Excedrin, Letterman and 'Nightline'. In short, insomnia is caused by life. 4 In a recent New York Times article on two new sleeping pills, one expert called insomniacs 'one of the largest potential pharmaceutical markets in the world.' Who needs tax cuts when you have sleep disorders to bolster the economy? 5 But hang on. Insomnia deserves a defense, not just a pill. 6 Especially in winter, I hear a lot of Chicagoans complain of insomnia, and it's certainly the season when my eyes are likely to pop open between 2 a. m. and 4 a.m. All of us who've ever suffered from insufficient sleep know its terrors—the crankiness, the disorientation, the hollow eyes, the bedraggled skin and spirit. We also know that one good night's sleep seems to cure almost everything, from premature aging to an Orwellian world view. 7 But the problem a lot of us mean when we talk about insomnia isn't insomnia. The problem is sleep deprivation, often caused by the lack of time to go back to sleep after a round of insomnia. Insomnia itself is something else, something that can come close to bliss. 8 Insomnia has given me exquisite moments in my life. In fact, it's when I finally gave in to my occasional insomniac bouts a few years ago that I came to relish those moments of stillness, freed from obligation, distraction and the hum of the busy, waking city. 9 In the tiny bedside light of 3 a. m. , with a concentration it's hard to muster in more chaotic hours, I've had the kind of ecstatic, fiercely engaged reading experiences it's hard to find past the age of 10. 'A Fine Balance.' 'A Civil Action.' Edward P. Jones' wonderful new novel, 'The Known World.' One reason I remember these books so vividly is that I read them in the quiet of the middle of the night, when words, feelings and ideas seep deeper than they do in ordinary waking hours. And does anybody who's not insomniac have time for magazines? By saying 'insomnia is caused by life' (Para. 3), the author means that ______.