In a few weeks, millions of high school seniors will embark on the grueling process of applying for admission to college.

It means all you seniors must keep your GPA up, get your resume sorted out, your letters arranged and your essays written while you choose whether to go with early decision or sweat it to spring.

In his excellent book "Acceptance," journalist David L. Marcus decodes this annual rite of passage while profiling a gifted college counselor, Gwyeth (rhymes with "faith") Smith Jr., and seven of his students at Oyster Bay High School on Long Island, New York.

"I wanted to show how a special counselor applied nearly four decades of knowledge to help Main Street students find, and afford, the right school," writes Marcus, a Pulitzer Prize winner who now works for Newsday, a Long Island newspaper.

Aside from being the alma mater of Thomas Pynchon, Oyster Bay High is no more than a reasonably good public school "with kids from all backgrounds," Marcus says. Its edge is Smith, a man keenly aware of every aspect and angle of the application process and deeply committed to his students.

His approach holds no startling revelations, except that his methods and precepts all stress what's best for the kid — and it's not the ivy on the walls, the bumper sticker on the parent's car, the pressure of the ethnic group.

"It's not about the brand; it's about the fit," Marcus writes.

KNOW THYSELF

"While some counselors pressed students to master the tricks of admission, Smitty was among those who got kids to first look at themselves," Marcus says. Students who know themselves will write better essays, perform better in interviews and have a better idea of what they want.

The personal essay gets a lot of attention, and in this Smith is aided by his life partner, an English teacher at Oyster Bay named Kathi Reilly. She stresses three "uns": "unusual details; unexpected twist; and understated tone."

Elsewhere, you'll find nuts-and-bolts applicant tips that reflect what Marcus calls Smith's "universal rule: Less is more."

The book is full of useful how-to information for an application gantlet that is complex and shifting and monstrously competitive. There were "a record 3.3 million students in America's class of 2008," Marcus writes, noting also that colleges were more selective:

"For most applicants to prestigious universities, 2008 was the year of rejection. Harvard admitted just 7.1 percent, compared to 9 percent the year before. Brown said no to 784 valedictorians."

EVERYONE GOT IN

At Oyster Bay, 109 seniors sent a total of 661 applications to 216 colleges. Smith's report card: "There were a few disappointments, of course, but all his kids had gotten in somewhere."

I grade Marcus and "Acceptance" A-plus for presenting an engaging, indispensably informative book. Smith retired after the 2008 class at age 63 and now offers his services privately for $330 an hour.

If you're thinking about spending money on an adviser, however, I suggest you and your Bright Well-Rounded Kid read Marcus first.

Either is money well spent, but Marcus could save you $300.