Television loves to portray park rangers as fit and polite, beaming dazzling smiles, displaying knowledge that knows no bounds, armed with nerves of steel, and with dashing personalities. That was evident in the 1970s series Sierra, and even in Lassie, when the rangers in question worked for the U.S. Forest Service.

And then there are the realities, as Andrea Lankford describes in her latest book, Ranger Confidential: Living, Working, and Dying in the National Parks.

Many of Ms. Lankford's rangers carry many of the attributes that television focused on -- rippling muscles, cute figures, an unquenchable call to duty. But in drawing from her dozen years wearing the gray and green with the National Park Service, she also exposes life in the trenches in ways that cast considerable tarnish on one of the most publicly revered government agencies. Early in their careers rangers must endure at-times squalid living conditions, pitiful pay, demeaning supervisors, and rescues that, if not horrifying in their own right because of the danger rangers must put themselves in, understandably could leave the rangers mentally suffering from the broken bodies of park visitors they must bag up.

"I, too relied on jokes to dismiss the many tragedies we saw," she writes early on. "I was another ranger who had to learn things the hard way. Rule Number 313: Tombstone humor is a Band-Aid placed over what may become a deep and festering wound."

Coming so soon after Ken Burns and Dayton Duncan lifted our spirits about the National Park System and park rangers with their 12-hour mini-series, The National Parks: America's Best Idea, Ms. Lankford's book at times is a pail of cold water tossed at the reader.

It's not so much that the conditions she lays out are unimaginable, for tell-all books on other industries and corporations and even the sports world lay bare shocking insider details we'd also prefer not to know. No, the reason for the shock, and disappointment, is due to the agency involved, the National Park Service.

For instance, Ms. Lankford tells us of:

* Highly placed rangers who, when angered, throw tantrums, throw safety helmets, kick medical kits, smack fellow rangers in the head with paddles, and yet .. "if you found yourself severely injured in an impossible place during impossible conditions, Keith Lober was the kind of asshole ranger you wanted dropping down a rope to see you."

* Sexual harassment within the ranks.

* Pitiful housing conditions for both rangers and concessions employees, of park employees killed on the job, of suicides in the parks.

Four concession worker hangings within four months, three of them fatal. If there was any connection between the 1994 hangings, my research failed to uncover it; but it was a trend that attracted the attention of a government agency on the outside, like the Occupational Safety and Health Administration. That year, during an investigation into the living and working conditions of the park's concession employees, a health inspector measured the daytime temperature inside one tent cabin. It was 112 degrees Fahrenheit.

* Of rescues in parks such as Yosemite, Grand Canyon, and Glen Canyon National Recreation Area that end in both tears of anguish and tears of joy, reminders not only that parks can be dangerous places but that highly skilled rangers can at times make the seemingly impossible possible.

Ranger Confidential is one ranger's 12-year-long diary, a book that both peers inside the heads of rangers and offers a glimpse of National Park Service management styles and care and feeding of its employees. The images are not always flattering, as noted above. And when two Yosemite rangers are honored in one year with two Department of Interior Medals of Valor for going above and beyond the call of duty, we're told "that the government would pay for only one medal for each ranger. Apparently that was all the NPS could afford."

But we also learn of individuals so determined and driven to be park rangers that they suffer beyond what most of us would.

Mary Litell started her career working for a concessionaire in Yosemite, where her first job had her sorting garbage, a rewarding task in that she could glance at Yosemite Fall. "For scenery like that, you'll pick loaded diapers and used condoms out of piles of greasy cans and bottles. You'll sling trash bags into the back of a slimy truck while it spits the backwash from beer-soaked cigarette butts at you."

Not only did Ms. Litell move beyond that menial task to become a distinguished heli-rappel ranger who had more than a few hairy experiences dangling on the end of a rope alongside El Capitan en route to rescuing injured climbers, but these days she's the chief ranger at Lake Mead National Recreation Area.

We also learn of one exemplary ranger, Cale Shaffer, who "was 22 but could pass for fifteen, and the Eagle Scout hadn't rubbed off him yet" when he became a ranger at Grand Canyon National Park in April 1997.

Mr. Shaffer arrived at the canyon in 1996 with a group of 16 at-risk youths pulled from "one of the poorest regions in Arizona." His job was to help supervise them with his boss while teaching park visitors about how to stay safe and to help out on search-and-rescue missions. Two days into this assignment, young Cale Shaffer decided that one day he would be a park ranger in the Grand Canyon. And one day he did in fact achieve that goal, and he quickly won respect for his work ethic and "compassionate demeanor."

Sadly, Ranger Shaffer had little time to mentor others or shed some of his attributes on those around him. In June 2000, while working as mountaineering ranger at Denali National Park and Preserve, he was killed in a plane crash.

What should be made of Ranger Confidential and the image of the Park Service it casts? In one respect, perhaps it should be realized that for an agency with some 20,000 employees, many who naturally are hard-charging and living on the edge, and whose budget is controlled not only by Congress but by political appointees, perfection cannot exist, no matter how idealistic the Park Service is viewed. And yet, despite the hardships and the inequities that exist in the agency, there is something to be said about wearing the gray and green, as Ms. Lankford seems to imply in her closing words.

After Cale's funeral, I threw all my ranger uniforms in a dumpster. This shocked my more sentimental ranger friends. I told them the act was incredibly therapeutic. I had to cut the cord. I had to move on.

But I kept the Stetson.

Today my Smokey Bear is taking up space in my garage. The leather band embossed with sequoia cones is faded and frayed. The felt is bruised and moldy. Despite these defects, I could get hundreds for my ranger hat on eBay. Yet I can't bring myself to part with it.