Letesha Dixon's fingers flew across the keyboard of an Army laptop as she tried to finish a final exam in her online time-management course before anything could force her from her desk. Then came the booming of mortar rounds exploding 300 feet away. The tent shook.

"I am under attack," Sgt. Dixon e-mailed her teacher. "I have to go!"

Hours later, she recounts in an e-mail to The Washington Post Magazine, the "all clear" signal sounded. Dixon emerged from a bunker, returned to her unfinished exam and resumed typing. Faster this time, she says, to avoid another interruption.

"The teacher was very cool about it all," Dixon writes. "I still got an A, even though I was late. Some teachers probably would've taken a letter grade, you know."

Stationed with the Army's 67th Combat Support Hospital in Tikrit, Dixon is a long way from the college experience she signed up for a year ago. Back then, the 30-year-old mental health specialist thought she had saved up enough leave so that she could separate from the Army and spend the spring semester at Howard University. She wants to go to medical school someday, she says. But the orders for her release didn't arrive in time to prevent her from being deployed to Iraq in January.

Though she is geographically and emotionally a world away from Howard's campus, Dixon considers an Army laptop in a tent in Iraq the next best thing. She was able to finish the time-management course she began taking in Germany, where she was stationed before her deployment. By this fall, she'd finished three more online classes -- library skills, film and ancient philosophy -- all through the University of Maryland University College.

"The thing about studying here is that you have to be able to drop everything in a second," she explains. "Sometimes study is interrupted by senior ranking people who are ordering you to do other things with your time; other times it's patients coming in on helicopters. When I sit down to write a paper here . . . I plan on being interrupted!"

So it goes for the soldier-student: Academic schedules are at the mercy of defense strategists. All-nighters include disruptions by enemy fire and incoming wounded. Group projects fall prey to weekend maneuvers.

Despite the challenges, hundreds of thousands of soldiers, sailors and Marines are taking college-level courses while serving their country -- and the opportunities to do so keep growing. Online study courses abound, linking American military personnel to faculty members in the United States, Europe and Asia. And campuses on or near U.S. military bases around the world provide a traditional college experience -- the chalkboard, Xeroxed course outlines and face-to-face discourse with a professor -- to thousands of others.

As a result, American soldiers are taking acting and Arabic classes in Bahrain, studying algebra in Quonset huts in Korea, and doing culinary course work in mess tents in Iraq. Marines are pursuing classes in psychology and philosophy in a guardhouse at the U.S. Embassy in Bangkok. Soon, there will be classrooms for soldiers in Afghanistan and Baghdad, provided by the military and staffed by UMUC teachers.

There isn't a battle-torn country in the world where American soldiers can't earn college credit if they are determined enough. But it isn't easy. Stress and scheduling conflicts lead many to drop classes midway through, UMUC officials say.

Abayomi Emiabata, a master sergeant in the Army National Guard, had planned on taking advantage of the military's generous tuition assistance when he registered for a UMUC class on terrorism two years ago. But then he received mobilization orders for Afghanistan. Uncertain of the availability of an Internet connection in the remote Hindu Kush mountain range where he'd be serving, the Fort Meade resident delayed, once again, completion of a bachelor's degree he'd started at Howard in 1984.

Schoolwork, Emiabata worried, would "complicate the dedication of a soldier to the task at hand."

"Because of the nature of my work in the military, if you drop out of a class, three or four years could go by before you can register for classes again," says Emiabata, who is back from Afghanistan and back at work on his degree. "You just have to figure you're going to be interrupted."

WHEN CONGRESS PASSED THE GI BILL near the end of World War II, it transformed the military by giving millions of veterans access to higher education. Today, many in the military don't wait until they leave the service to take advantage of tuition-assistance benefits.

More than one-quarter of today's active-duty military personnel are in college, according to the Pentagon. Theysigned up for 680,000 classes in 2002, up from 630,000 in 1996.

UMUC is the largest and longest-running adult education provider to the military, with a $35 million Army contract to offer courses and programs at 87 sites in the United States, Europe, Asia and the Middle East.

"I've got teachers calling, asking to be sent to Iraq," says UMUC President Gerald Heeger, who is overseeing the creation of an academic outpost in Baghdad. "The logistics may be more extreme, but they're the same logistics of holding class in Shady Grove. The only thing that changes is the geography, not the philosophy."

And the geography is always shifting. Last spring, for instance, when the Pentagon announced it would be moving 20,000 troops from just north of Seoul farther south, UMUC began mobilizing its professors to move with them.

"As in bygone years when there were 'camp followers,' we will follow camp," explains Joe Arden, head of UMUC's Asian division, which employs 400 instructors to teach 22,000 students.

UMUC isn't the only player on the educational battlefield; a number of other institutions also provide educational opportunities to military personnel. They include the University of Phoenix, which has 7,000 active-duty students in its online degree program, and the newly launched Army University Access Online, or eArmy U, the largest education-assistance initiative since the GI Bill. Launched four years ago at a cost of $600 million, eArmy U plans to eventually enroll more than 80,000 soldiers in its classes -- part of an effort to persuade more active-duty soldiers and reservists to remain in the military.

Most of the programs have developed formulas to award academic credits for military experience and for classes taken at other colleges. The result: It is becoming possible for service members to complete degrees before leaving the military.

And the military is helping to pay for it. Tuition assistance has increased from $26.6 million in 2002 to $50.2 million last year, according to the Pentagon's office of voluntary education. For an active-duty service member, the military will pay up to $250 per credit hour, for a maximum of $4,500 a year.

In many ways, rising enrollments reflect the changing face of the American military. With their increasing emphasis on technology, the armed forces have come a long way from "Project 100,000," the Army's Vietnam-era effort to enlist soldiers without high school diplomas.

"Today's soldiers are smarter than ever before, and they're demanding to go to school," says Dian Stoskopf, the Army's head of voluntary education. "New programs are making it more attractive for them to stick to their studies."

Studying stateside is one thing. Studying through a deployment is another. That's why most soldier-students don't complete degrees until after they leave the military, and why some never complete them at all.

"Our military people are operating under a very heavy workload," says Rebecca Rice, a member of UMUC's military advising team. "We work on forming relationships that can help them with all the transitions they're going through" to keep them from dropping out.

Last year Mary Caldwell, an Air Force Reserve nurse from Kettering, Ohio, completed an online course in community health with the University of Phoenix while assigned to the air staging facility in Baghdad. By day, she patched up wounded soldiers and loaded them onto C-17s for their flights out of Baghdad. At night, she did her course work on her laptop, then waited for the chance to transfer completed assignments onto government computers, which, unlike her own, were connected to the Internet.

"My counselors and friends thought it was awfully ambitious, and they talked to me about getting a waiver for the class," says Caldwell, 52, who received an A for a paper about her efforts to get troops to wash their hands before meals. "But I know that if I pushed it back I may never have done it."

Like most service members in continuing education programs, Caldwell has taken courses on and off for years in pursuit of a master's of science in nursing. Also typical is the driving force behind her studies: a need to prepare for eventual separation from the military. She plans to use her master's degree to go into palliative -- end-of-life -- care. "I'll be able to retire in six more years," Caldwell says, "and I'll have options."

IT IS AN EYE TO THE FUTURE that drives Letesha Dixon's rapid-fire online study schedule.

She moved to the District in 1992 to attend Howard. Seven years later, with no degree, money running short and school loans mounting, Dixon signed up as a Russian linguist with the Army, which promised to repay her loans and help her finish college. Four years ago, she decided to pursue a lifelong interest in medicine, reclassifying as a mental health specialist and setting her sights on medical school.

Her work in the hospital emergency room in Tikrit focuses almost exclusively on counseling for combat stress and grief, a heavy charge for someone with little psychological training. "We are just winging it, while trying not to buckle under the stress of hearing these stories over and over, and seeing these soldiers struggle with it," writes Dixon, whose husband, Spec. Woodson Joseph, a medical supply specialist, is stationed at the same hospital and dealing with many of the same issues.

At least three dozen soldiers in Dixon's unit are working on undergraduate degrees, and a few are working on master's degrees, she says. Over the summer, she helped build the hospital's "education center." It's a standard tent that houses six Army laptops and a printer. She often has to use more than one laptop to get each paper done, so she is careful to save her work on a memory stick.

The interruptions, she says, occasionally fill her with doubts about her academic mission. But her studies give her a sense of purpose.

"Sometimes, someone comes in all hurt up, or even dies, and I get bummed out wondering what is the point of even going to school when I may never leave this place," she writes. "But sooner or later this passes, and I'm back at it. Actually, I use the classes as my buffer from this reality. What I want to be is a student, so when I'm in class, I'm able to forget about all of the other stuff around me and be just that, a student."

Mary Grace Gallagher is a frequent contributor to the Magazine.