Rob Sica helpfully points us to Anthony C. Edwards' The Plain Sense of Things.
One of the Amazon reader-reviewers describes the book as aimed at this question: "How do we give our lives meaning in an age where religion has lost its POWER?" Setting aside whether that's an accurate statement of the book's focus (the book preview signals related but slightly different concerns), I'd go one level deeper: How do we give our lives meaning when we've discovered that religion never had the power we thought it did?