SAN FRANCISCO — As optimistic as Americans tend to be, those who get caught in one of the health-care system's costly gaps often are shocked to discover how fast even a comfortable, middle-class life can slip away.

SAN FRANCISCO — As optimistic as Americans tend to be, those who get caught in one of the health-care system's costly gaps often are shocked to discover how fast even a comfortable, middle-class life can slip away.

That's the common thread in author Jonathan Cohn's new book "Sick: The Untold Story of America's Health Care Crisis — and the People Who Pay the Price." It examines health and insurance predicaments that sneaked up on working Americans and frequently left them destitute or worse.

The book's personal accounts and historical context bring the issues into focus at a time when many states are experimenting with health-care reform and the nation appears ready to consider alternatives. Nine months before the first primary ballots are cast in the 2008 presidential election, many of the candidates and nearly all the Democrats already have proclaimed health care a top domestic policy issue.

The political momentum is building as more voters become anxious about their ability to stay insured — and insured enough to keep them from falling on hard times, Cohn said. Even so, 61 percent of companies offered at least some of their workers access to employer-provided coverage last year, although that portion has dropped from 69 percent in 2000, according to the Kaiser Family Foundation.

"People rarely realize how vulnerable they are," Cohn said. "You have people who have done what they would consider everything right. ...They have jobs; they have families. They're going about their business and then boom, some medical catastrophe strikes."

"Suddenly they discover that not only do they have to deal with this medical catastrophe but for some reason they can't pay for their health care," he said. "Either their insurance has run out, they don't have their insurance or their insurance doesn't cover what they need. It's amazing to me how quickly somebody's life can unravel because of that."

Among the people Cohn interviewed across the country: a retiree who sold his house to pay for his ailing wife's medications and a man who lost his job, picked up a temporary one with no benefits and watched helplessly as his wife died of cancer. In Texas, a young mother battled her insurance company to cover therapy that could help her son, born extremely premature, to walk.

Employer coverage and health insurers aren't the only systems failing some of the people who need them most, the book shows. Because of overcrowding, a 55-year-old Boston woman suffering a heart attack couldn't be transported to the only nearby emergency room that could perform a life-saving procedure, Cohn writes. The hospital to which she was taken tried to revive her but couldn't perform catheterization and she died.

Health-care costs have ballooned since the early 2000s, and employers have responded by shifting more costs to workers. The problem with that is many plans designed to sensitize consumers don't distinguish between those who would do well to rein in their out-of-pocket spending and those who can't cut back without paying a hefty price in severe illness and disability, said David Knowlton, a board member for the HealthWell Foundation in Trenton, N.J.

"One perverse consequence of that is people with chronic illness who suffer further pain, disability or death if they don't take their medication fall into the same bucket" as people who have more discretion on such matters, he said.

HealthWell provides financial assistance to qualified applicants who have health insurance but can't afford their prescription-drug co-payments. The outfit is funded by unrestricted grants from pharmaceutical companies, Knowlton said, declining to name them.

Some drugmakers offer patient-assistance programs directly.

"In the co-payment arena, people find themselves with this completely unanticipated expense that goes on and on and on," Knowlton said. Depending on their income, some patients can get overwhelmed by co-payments that can hit thousands of dollars a month for conditions such as rheumatoid arthritis, for which drug treatments are among the priciest on the market.

There are other ways consumers can get crushed financially, he said. "Some of the lesser-quality health plans have lifetime maximums, so people hit those caps and they blow through the plan."

To remedy such ills, Cohn favors universal health insurance, which he argues is necessary because the private sector can't and won't solve the problems on its own. Many companies stop short of endorsing a government-run insurance system, but a growing number of large firms once vigorously opposed to an overhaul are pushing for more than just incremental changes as the employer system becomes ever more strained.

Michael Cannon, director of health policy studies at the Cato Institute, a libertarian think tank in Washington, disagrees that competition among private health insurers has been given ample opportunity to work. Where Cohn may see a failure of the free market driving the stories he illustrates, Cannon said he sees "big government's fingerprints."

The individual insurance market, riddled with problems of access and affordability since it's underwritten for a single person or family instead of a large group, would work better if people could purchase across state lines and without having to buy into a host of state-mandated benefits, Cannon said.

The individual market also suffers because so many healthy people are drawn out of the pool by employer-provided insurance, Cannon said. "As badly damaged as the (individual) market is now, that coverage stays with you from job to job and without a job. You have to make the premiums, which is not easy, but the tax code makes it more expensive than it has to be."

"What I would propose is to level the playing field between employer-provided insurance and individually purchased insurance," he said. "Then people don't have to worry about that huge gap of losing coverage when you lose your job."

But Cohn said insurers are under pressure to accept less risk, which means consumers end up less protected. "If you keep following this trend to its logical conclusion I think you end up in a situation not unlike the situation in the 1920s before we had health insurance, where in effect there was a lottery: If you were healthy you were great, and if you got sick you were in trouble."

"This is the direction our system is going in," Cohn said, defending universal care. "If we do nothing we will see a transfer of financial responsibility and risk onto the people who can least afford it. You have to ask yourself: Is that the kind of society you want to live in?"

Kristen Gerencher is a reporter for MarketWatch in San Francisco.