In 1907, the Appalachian Mountain Club published a little book called “Guide to the Paths and Camps in the White Mountains.’’ As its rather wordy title made clear, it was a collection of maps and descriptions of trails through the Presidential Range and beyond.

Through printing after printing, the book changed titles — the 30th edition of what is now known simply as the “White Mountain Guide’’ was just published — but its basic structure remained largely unchanged: It was an adventure book without a plot.

Then some hikers decided that it most certainly did have a plot, a very long and simple one: To finish the book, you must walk every trail in it, all 1,420 miles.

Called “redlining’’ — the idea being that you draw a red line over every completed trail — the challenge has become increasingly popular over the last decade.

“It used to be this obscure thing, but I have people coming into the shop all the time now asking about it,’’ said Steven Smith, the owner of the Mountain Wanderer Map and Book Store in Lincoln, N.H., and the editor of the latest edition of the guide. He’s also the seventh person to redline, a feat he finished in 2010, using the 28th edition of the guide.

“So many people have finished the 4,000-footers,’’ Smith said, referring to the well-established tradition of climbing the 48 tallest peaks in the Whites in New Hampshire, “and now they’re looking for new challenges.’’

Redlining is indeed a challenge, one that took Smith 30 years to accomplish. You’ll need to climb all 48 of those peaks, probably more than once because there may be several routes to the top and many side trails and spurs. Redliners say you’ll easily walk 3,000 to 4,000 miles trying to complete all the trails. By comparison, the entire Appalachian Trail, which stretches from Georgia to Maine, is 2,200 miles.

But much of the hiking takes place outside of the popular trail networks that support the highest peaks, leading redliners to obscure, seldom-used trails all over New Hampshire and western Maine. Many of the trails are a challenge to simply find and require strong map and compass skills to navigate.

But it is those trails that are, for many, the chief appeal of taking on the challenge of redlining.

“It’s a complete misconception that the beauty of the Whites is the 4,000-footers. That is so far from the truth,’’ said Philip Warner, who lives in Malden and finished his redline in July. “The beauty is so far spread, and so unbelievable. And that is the driving motivation to be a redliner.’’

Beth Zimmer, a middle school guidance counselor from Meredith, N.H., who is just a few hikes from finishing her quest, said that being forced to chase new vistas keeps every hike fresh.

“When I hike the same trail repeatedly, I know what’s coming,’’ she said. “I like the novelty of the unknown. It’s forced me to hike trails that are very difficult, very remote, but at the core you’re really in the moment. It’s like driving down a country road you’ve never been on and your eyes see the stone walls and the apple trees that people who use that road every day stop noticing.’’

The recent surge in interest in redlining can be traced to the simple fact that it was given a name and a home on the Internet, thanks to Ed Hawkins, a 71-year-old who is still knocking off alpine peaks with two artificial knees. Hawkins is a “gridder,’’ a name given to those who climb all forty-eight 4,000-foot peaks 12 times each, once in each month of the year. Hawkins has done the grid six times and maintains a website celebrating hiking in the Whites, 48x12.com.

“A few people were doing it but it wasn’t really being recognized,’’ Hawkins said, “and it fit with the general idea of our website.’’

Now, if you hike all the trails, you get your name listed on the site, and Hawkins will mail you a special patch. So far, there are 36 names on the list – all but four of them have been in the last 10 years – beginning with Jon Burroughs in 1991, who was something of an accidental pioneer.

“Redlining wasn’t a thing when I did it,’’ said Burroughs, who knocked off the trails mostly because he was helping to edit the guidebook and walked nearly every mile with a surveyor’s wheel to record the distance of each trail. “Then Ed started this club and gave it a name, and I kinda realized, wait, that includes me. I reached out to him, and he told me I was the first one to do it, even though I didn’t realize there was an ‘it.’ ’’

It is definitely an “it’’ now, and many hikers had been patiently awaiting the 30th edition. Each edition varies slightly, with some trails added and some removed, and hikers choose one to stick with.

But there are still several hikers out there in the woods working on the 29th edition, including Mike Cherim, who finished his redline just over a week ago. Cherim, who owns a hiking guide company in North Conway, N.H., called Red Line Guiding, said that finishing was bittersweet. But his grand takeaway from walking every trail in the book is an understanding of the connectedness of the Whites. He recently stood on top of Mount Bartlett and realized that he could identify 87 mountains in front of him.

And even though he’s done with the book, Cherim said that doesn’t mean he’s done seeing new things in the Whites.

“Between the red lines, there’s a lot of green,’’ he said. “There’s still so much to see if you go off trail.’’

Billy Baker can be reached at billy.baker@globe.com. Follow him on Twitter @billy_baker.