Four boys dangle from the tree in the Hendersons' front yard in Tempe, Ariz., enjoying the long summer days that yield plenty of time for climbing, swimming and staying up late.

They roam from the back to front yard by clambering over a cinder-block wall still baking hot from the sun. In their world, blisters and skinned knees aren't enough to pause their play. They even dig out their own splinters.

This summer, 10-year-old Luc Henderson and his friends Jordan Watt, 10, and 11-year-olds William Middleton and Connor Hanson have been immersed in "The Dangerous Book for Boys" by British brothers Conn and Hal Iggulden.

The big book with a stop-sign-red cover is a guide to boyhood, or at least what boyhood should be. It contains an almost lost world of tree houses, bows and arrows, and pirate flags.

In the beginning of the book, the authors write, "In this age of video games and mobile phones, there must still be a place for knots, tree houses and stories of incredible courage." There's also a sampling of Shakespeare, Latin phrases, and seven poems every boy should know.

Scott Henderson, Luc's dad, watches the boys drop from the tree and race through the front yard in mock battle. As a boy growing up in Decatur, Ill., Henderson would take off for hours, swimming in a nearby creek and building forts from leftover planks in the barn. He says, "These boys don't have the kind of freedom I did."

Parents keep their kids close to home now, apprehensive of strangers and traffic. But the big, red book encourages adventure and a little risk — all under proper adult supervision, of course. There's nothing of great peril within its pages, though a kid could catch his pants on fire with the pocket light on page 143.

ADVICE FROM THE BOYS

Here's the boys' advice, as well as tips from the book, for adding adventure to a boy's days:

• Build a tree house. In the front yard, Luc and his dad have built — and are still adding to - an elaborate tree house perched 18 feet high that features an 8- by 11-foot covered room, a retractable ladder and a plastic bucket on a rope for hauling up essential equipment such as flashlights and snacks.

"We have great adventures up there," Luc says.

The authors say that, along with a canoe or a small sailing dinghy, a tree house is still one of the best things a boy can own, beating out even the best video games. They recommend that any fort feature a skull and crossbones.

Out back, Luc and his friends have built another fort with castoff plywood and carpet remnants. The boys climb onto the roof, scanning the neighborhood. Jordan says, "I love this place. This is where we really get to do everything. We can hide in here, climb and hang out."

• Be brave. Summer is as good a time as any to try something new. A zip line stretches between two trees, allowing the boys to fly across the front yard while dangling from a pulley. William decides to try it for the first time, taking a leap of faith from the tree limb into nothingness. The other boys cheer him on. "You can do it, Will," Luc assures him. William sails safely to the ground. He grins triumphantly: "That was fun!"

• Make a bow and arrow. Firing an arrow is fun, the boys say. Not because they're trying to hit anything, but just to see how far it will go. William stretched string from end to end of a piece of ash to make a bow. Luc made one, too, out of a branch, but his dog Boom ate it. Both boys are allowed to fire only at parent-approved targets.

The book provides step-by-step instructions for making a bow and arrow, fashioning an arrowhead from flint and cutting notches with a Swiss Army knife. The authors caution: "Remember at all times that it is a weapon. Weapons are never pointed at other children."

• Think. Summer gives boys time to ponder worldly issues rather than spelling tests and science projects. From the section in the book on girls, William says he learned, "Women are generally complicated and you may never understand them." The other boys agreed, saying that it's best just to flatter them and give them chocolate.

• Learn to handle a pocketknife. A Swiss Army knife is listed as the No. 1 piece of essential gear in "The Dangerous Book for Boys." They are handy when a boy needs a screwdriver or to whittle a stick. William gave Luc his first pocketknife for his birthday in March.

Luc was thrilled. He immediately pushed open a blade and sliced open his thumb. William says, "He had it about 10 seconds before he cut himself."

• Fight evil. Two chapters are devoted to such famous battles as Waterloo, Balaclava and Gettysburg. The book tells boys, "As well as being formed in new laws and sweeping cultural movements, history is made on the battlefield, with entire futures hanging on the outcome."

For their own battles, the boys divide into teams, making up the rules of confrontation as they go along. William says, "We play make-believe because then we can be anything."

Cornered by Luc, who is armed with two plastic swords, Connor yells, "Somebody help me!" Wielding a green lightsaber, Jordan comes to the rescue, and Luc runs. Jordan yells after him: "Stop running from a fight! Be a man!" Or at least a boy.

GEARING UP

"The Dangerous Book for Boys" names these simple pieces of equipment as essential for handling a wide range of play situations.

• Swiss Army knife. Use for jobs requiring a screwdriver, removing splinters or whittling sticks.

• Compass. You really should always know where north is.

• Handkerchief. There are so many uses for a piece of cloth, from preventing smoke inhalation or helping with a nosebleed to offering one to a girl when she cries. Big ones can be folded into slings.

• Box of matches. You must be responsible.

• A shooter. Your favorite big marble.

• Needle and thread. Good for sewing a wound on an unconscious dog or repairing a torn shirt. If the thread is strong, it can be used for fishing.

• Pencil and paper. Keep observations or perhaps a shopping list.

• Small flashlight. In case you are in the dark and need to read a map.

• Magnifying glass. For general interest.

• Band-Aids. One or two, or a piece of cloth bandage, just in case.

• Fishhooks. With strong thread, a hook, a stick and a worm, you have a chance of catching something.

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