Life went on high alert four years ago, when my book came out. "The Trouble with Islam Today" challenges sexism, anti-Semitism and other prejudices that pervade the contemporary Muslim world. I quickly became an internationally best-selling author, cheered by people who believe in universal human rights.

Along with their support, however, came chilling messages from would-be assailants: "You will pay for your lies," "Enjoy your short stay on earth" and "This is your last warning."

Do I have a death wish? No. But what would be sadder for me than a life ended is a life wasted.

As a Muslim woman lucky enough to live in an open society, I insist on using my precious freedom to think, express, challenge and be challenged. Put bluntly, I have the opportunity shatter deadly silences. How irresponsible would it be not to?

I've been asking questions since childhood. My mother, a devout Muslim from Africa, brought me and my sisters to Canada. We attended a public school during the week and an Islamic school on the weekend. There, I'd be lectured about the inferiority of girls and Jews.

From under my scarf, I began defying the hate. My mother struggled with my outspokenness. "Whatever you do," she lovingly warned me, "please don't anger God."

So I had to ask: Was infuriating my teacher the same as angering my Creator? Did God really want me to be a second-class citizen? Did he seriously condemn an entire people - Jews - to eternal hell? In short, is this the same God of mercy and compassion that Islam's holy book, the Koran, describes at the start of almost every chapter?

"Either you believe or you get out!" my teacher bellowed one afternoon. I kicked open the hefty door and yelled back, "Jesus Christ!" Little did I realize just how memorable such an exit line would be: Jesus was a Jew.

I walked away from my Islamic school but not from my Islamic faith. Over the next 20 years, I took time to search for the beauty in my religion.

That's when I discovered Islam's own tradition of critical thinking, debate and dissent. It's called ijtihad (ij-tee-had). By engaging in ijtihad, Muslims can modernize our mindsets. We can be faithful and thoughtful at the same time. We can also live our faith without fear.

Of course, all people of faith have moments of wondering whether we've transgressed. Which is why courage is not the absence of fear. Courage is the recognition that some things are more important than fear.

To me, much more important than fear is freedom - the ability to exercise it and grow from doing so. That vision is entirely consistent with the spirit of Islam.

FOR EXAMPLE, the Koran contains three times as many verses calling on Muslims to think, analyze and reflect than ones that tell us what's absolutely right and wrong.

I believe so passionately that Islam and freedom can be reconciled that I've produced a film about this mission. "Faith Without Fear" will be screened in Philadelphia on Saturday. I'll field questions from the public and, as always, pose a few of my own.

My hope is that all viewers, Muslim and not, will be inspired to conquer their personal fears - the fear of being ostracized (or worse) in their communities, the fear of offending minorities in a multicultural world and, above all, the fear of thinking freely.

By confronting our fears, we can finally take ownership of the solutions before us. This, too, might be frightening, but the status quo is a far bigger risk.

Despite all the death threats, I'm hearing more support. Most gratifying is my mother's blessing. Recently, she slipped a card into my suitcase. The front of it reads, "Bravo." Inside, she writes, "I'm so proud of your achievements. You go, girl!"

That's my credo, too. In an open society, using our voices isn't merely a right - it's an obligation. May more people of faith marshal our voices to break deadly silences - for good. *

Irshad Manji is the author of "The Trouble with Islam Today: A Muslim's Call for Reform in Her Faith" and director of the Moral Courage Project at New York University.