We are delighted to welcome you all to a new global conversation about what is perhaps the most pervasive and least understood force in human affairs: religious faith. It is a subject about which many people have strong opinions, about which many people care passionately-but about which there is, in our view, far too little constructive discussion and debate.

It is our hope that we can offer a small remedy for this with the On Faith online conversation. We have assembled a distinguished panel of experts -- believer and nonbeliever, clerical and lay, academic and activist -- which will answer a weekly question. Our own qualifications to lead this discussion are as divergent as the members of the panel. Sally Quinn, of the Washington Post, was a self-declared atheist from the age of 13. She became convinced only recently that religion was not a subject to be dismissed or disdained and, has been moved by the yearning for something beyond oneself that drew so many people to search for faith, especially after 9/11. Jon Meacham, of Newsweek, considers himself a believing, middle-of-the-road Protestant, educated from an early age in religious schools and fascinated by faith. In the spirit of diversity and dialogue we invite -- no, encourage -- readers of every background to respond to the questions online.

From the caves of the Afghan-Pak border to the cul-de-sacs of the American Sunbelt, faith shapes and suffuses the way billions of people-Christian, Muslim, Jewish, Hindu, Buddhist, and nonbelievers -- think and act, vote and fight, love and, tragically, hate. It is the most ancient of forces; as Homer said, "All men need the gods," even the most ferocious atheists find themselves doing intellectual battle on a field demarcated by the forces of the faithful.

And so, in a time of extremism -- for extremism is to the 21st century, as totalitarianism was to the 20th -- how can people engage in a conversation about faith and its implications in a way that sheds light rather than generates heat? At The Washington Post and Newsweek, we believe the first step is conversation -- intelligent, informed, eclectic, respectful conversation -- among specialists and generalists who devote a good part of their lives to understanding and delineating religion's influence on the life of the world. The point of On Faith is to provide a forum for such sane and spirited talk. Perhaps Hebrews 11 puts it best when it asks, "What is faith? It is the confident assurance that something we want is going to happen. It is the certainty that what we hope for is waiting for us, even though we cannot see it up ahead."

From the nature of evil to reformation in Islam, from the theological objections to fetal stem-cell research to the history of scripture, from how to raise kids in multifaith households to the place of gays in traditional churches-of the asking of questions, to paraphrase Eccleisastes, there shall be no end. But we think that the online world, with its limitless space, offers us a unique opportunity to carry on a fruitful and intriguing and above all constructive conversation about the things that matter most.