Beryl Markham, a heroine of the 20th century, wrote, "I learned what every dreaming child needs to know - that no horizon is so far that you cannot get beyond it or above it."

Two 21st century heroines, Norwegian Liv Arnesen and American Ann Bancroft, by nature explorers and adventurers and by profession schoolteachers, took on the challenge of crossing Antarctica. This they did not alone nor in an egotistical search for glory, but in tandem with a large team of supporters and funders, and in a worldwide web connection with schoolchildren.

The book works by jumping from micro to macro, from the most personal daily journals to the most universal aspects of this incredible feat, how it was followed by the team and by the public. We see the two women meet and assess one another. Liv told of growing up desperate for reading material about heroic women, and finding so little that she seized happily on a book called Amor on Skis - "mor" means "mother" in Norwegian - with the predictable disappointment.

Both girls grew up wanting to accomplish more than women are "supposed to" and were met throughout their adult lives with tiresome and stupid resistance - they were told, "women don't belong in Antarctica." Both Ann and Liv had read of the attempts of Sir Ernest Shackleton to cross Antarctica and were inspired by that. Both had already accomplished more than most other women in outdoor sport. Among their accomplishments: Arnesen had led the first unsupported women's team across the Greenland icecap, and Bancroft was the first woman in history known to have reached the North Pole by ice. Both women, in their forties, were ready for a new goal - to be the first women to cross the landmass of Antarctica, something only accomplished previously by one team of two men.

Ann and Liv found they were kindred spirits - they practiced singly and together, cross country skiing on gravel roads with car tires tied to their waists to simulate the heft of the equipment they would be carrying across the Pole. The book describes in fascinating detail the various things they took with them - so exacting were they concerning weight requirements that Ann cut a toothbrush in half in order to balance out the weight of a photo she wanted to carry.

Behind the story of their personal day-to-day struggles with cold, unpredictable and often very hostile weather, pain and the fear mainly of failure, we have the viewpoint of the team that made the journey possible by soliciting funding, publicity and donations of equipment, and supported them bravely from the sidelines. A lawyer battling cancer tells his own story and provided much-needed inspiration for the women as they trudged along, sometimes unable to meet what seemed like impossible daily goals. The children who were avidly following the trek via the Internet and the public who heard satellite phone transmissions from the two explorers also gave them the next gasp of breath needed to push on when the odds seemed insuperable.

Literally, the next breath could come in the form of a serendipitous wind that lifted them to the Pole when all seemed lost for making their deadline. The women had only a small period of time - Antarctic summer - in which to accomplish their journey. They could have been rescued at any time, which meant that they could have given up at any time, but despite sometimes body-searing pain, the mad boredom of a diet consisting mainly of oatmeal, oil and chocolate, and hardships such as having to spend four hours a day boiling enough water to eat and drink and making bathroom arrangements "as fast as possible" in the ice - they persevered and became the heroes they'd dreamed of being when as little girls they'd read the adventures of Shackleton.

Both women swear they don't like the cold - they've just learned to dress for it. Through their eyes we see that ice can be beautiful, remote places have a bounty of spiritual gifts, and every day a new experience and a new challenge to courage. It is to be hoped that young women will read this book, which offers a fresh look at what two rather ordinary (and truly extraordinary) middle-aged women can do when they set their minds to it. You can read more about their adventure and latest plans at the website they created to follow the crossing - www.yourexpedition.com.