The financial firm Cantor Fitzgerald lost more employees on 9/11 than any other company: 658 killed after the first plane hit the North Tower of the World Trade Center. To mark the 25th anniversary of the terrorist attacks, The Cantor Fitzgerald Relief Fund has published a book, “The Families: 9/11 Anthology of Love, Loss, and Lessons of Resilience,” edited by Edith Lutnick, cofounder, president, and executive director of the Cantor Fitzgerald Relief Fund, and Caroline Aiken Koster, the fund’s general counsel. Below is an essay by Koster, adapted from the book, which also includes essays, poems, letters, and speeches from families…