BOSTON -- In his book, “The Great Divorce,” C.S. Lewis tells the story of a man in purgatory who is enslaved to a red lizard who lives on his shoulder and whispers things in his ear.

The man is approached by an angel who offers to kill the lizard, but he responds, “Please -- really -- don’t bother. Look! It’s gone to sleep of its own accord. I’m sure it’ll be all right now. Thanks ever so much.”

At the kickoff of the 2008 fall Christ Speaks in the City lecture series Sept. 20, Angela Franks spoke about the insight of Lewis.

“I think C. S. Lewis really understands something -- that we get used to our misery, and we can’t imagine how to live without it, even if we grasp that it’s not going very well,” she said.

In the novel the man eventually allows the angel to kill the lizard, which turns into a white horse that the man rides into the deepest “heart of heaven.”

“It’s our most crippling sins and weaknesses that God uses to carry us up into his heart,” said Franks, who has a doctorate in theology from Boston College.

The lecture series, sponsored by the Archdiocese of Boston’s Vocations Office, began last fall with the intent of attracting young professionals to the Old Statehouse in downtown Boston to hear speakers witness to how God is working in their busy lives. Four talks were held in fall 2006 and another four were held in spring 2007. This fall season will consist of one talk each month from September to December on Thursdays at noon.

Father Daniel Hennessey, director of vocations in Boston, said that the last two seasons of Christ Speaks in the City were so well received that the Vocations Office has continued to organize them.

“People really love to hear the witness of others who are striving to live the faith just like they are,” he said. “This year we are hoping that the enthusiasm that so many people have had for it will continue and that it will be an opportunity for some Catholics who haven’t been connected to the Church.”

The series is just one invitation to fallen-away Catholics to full participation in the life of the Church, he added.

During her talk, Franks said she too knows what it is like to fall away from God. A young woman who professed faith in God, Franks was a “practical atheist” who struggled with an eating disorder. Her battle with anorexia was an attempt to control her own body, her own feelings and to find a substitute for God.

She quoted St. Augustine who said, “O Lord, you have made us for yourself, and our hearts are restless until they find their rest in you.”

“When I began obsessively dieting it was to fill that Augustinian restlessness in my heart,” she said. “I lost my sense of self.”

Franks said she lived as though God did not exist and felt she was better off trusting herself.

“I treated God like a well-meaning but distant and highly-eccentric uncle who has a lot of wealth and isn’t sharing it with me and that makes him a little bit suspicious and certainly not reliable,” she said. “I was like a drug addict that wanted to be released from the latest scrape so that I could go on using drugs with impunity.”

Franks said she wanted all the happiness that comes with following the Lord without actually following him, but humans are not made to be happy without God.

“We are made for happiness, which means we are made for God. Nothing else can satisfy,” she said.

Franks was born and raised in West Virginia, received her bachelor’s in theology at the University of Dallas, master’s in philosophy at The Catholic University of America in Washington D.C. and doctorate in theology from BC. She and her husband, J. David Franks, are coordinators of the Massachusetts Catholic Conference’s marriage initiative and parents of three children.

Speaking on the topic, “A Journey of Peace: What the Church Offers Women (and Men),” Franks addressed specifically the challenges women in the current culture face. Many use substitutes for God like shopping, worrying, money, sex and career advancement. They think, “If I only had that, then I would be happy.” They are searching for their own way to be happy, not God’s, and their thoughts colonize their minds, crowding out thoughts of God, she said.

Women often struggle with their body image and seek to control their weight and even their fertility, she added.

Margaret Sanger, founder of Planned Parenthood, argued that women were oppressed by their own bodies, not sexist attitudes. Their bodies “forged chains,” broken by birth control. Instead of recognizing fertility as a gift, she saw it as a burden, Franks said.

Franks said that Sanger and the women who buy into this argument are trying to follow their own way, controlling their bodies. Instead, God wants them to give their entire selves, including their fertility, in the commitment of lifelong marriage. He wants their love to be faithful and fruitful, like his own, she said.

Franks added that she found joy when she let God back into her life. Like the man in Lewis’ “The Great Divorce,” she allowed God to help her in recovering from anorexia, killing her red lizard.

“I discovered, to my amazement, that God wanted me to be happy even more than I wanted me to be happy,” she said. “Christ is just waiting for a chance to surprise us with his generosity.”

The next Christ Speaks in the City lecture will be held at the Old Statehouse on Oct. 18 at noon. Deacon Kenneth N. Ryan, a permanent deacon at Sacred Heart Parish in Weymouth, will speak about “The Journey of a Deacon: Serving Christ at the Altar and the Marketplace.” The other dates will be Nov. 18 with the University of Massachusetts Focus Missionary Team and Dec. 13 with Cardinal Seán P. O’Malley, who speaks at one lecture each season.