Dozens of books have been written about the spiritual but not religious (SBNR) in the past 15 years as this secular demographic continues to gain ground. Here are 10 of the best, in no particular order.

1. Spiritual, but Not Religious: Understanding Unchurched America

Robert C. Fuller, a professor of religious studies at Bradley University in Peoria, Ill., was the first to offer a comprehensive look at the beliefs and practices of Americans who are living spiritual lives outside organized religion. In his 2001 book, he argues that alternative spiritual practices are nothing new — they date back to the colonial era, when church membership was low and interest in astrology, numerology, magic and witchcraft ran high.

2. Grounded: Finding God in the World — A Spiritual Revolution

Christian writer Diana Butler Bass points to a spiritual transformation: people may be leaving church, but they are finding God — or at least godliness — in nature and in community.

3. Relig-ish: Soulful Living in a Spiritual-but-Not-Religious World 

“Spiritual misfit” and former ordained minister Rachelle Mee-Chapman offers up a guidebook for creating SBNR habits, traditions and practices.

4. Relax, It’s Just God: How and Why to Talk to Your Kids About Religion When You’re Not Religious 

Parenting columnist Wendy Thomas Russell reports on results from her survey of 1,000 non-religious parents and offers secular parenting advice on teaching kids about God, religion and spirituality.

5. Belief Without Borders: Inside the Minds of the Spiritual but Not Religious

Hailed as spiritual pioneers and, at the same time, derided as shallow fence-sitters, the SBNR have rarely been asked to speak for themselves. Theologian Linda A. Mercadante gives them the chance to do just that by conducting in-depth interviews with almost 100 American, mostly middle-aged SBNRs.

6. Choosing Our Religion: The Spiritual Lives of America’s Nones 

Religious studies professor Elizabeth Drescher examines the “nones” — those who answer “none” when queried in American surveys about their religion (almost 25 percent of the population). The nones include the SBNR as well as atheists, agnostics and humanists. Drescher reveals that many of them find the most meaning in the “Four Fs” — family, friends, Fido and food.

7. The Nones Are Alright: A New Generation of Believers, Seekers, and Those in Between

About one-third of millennials are nones. Journalist Kaya Oakes interviews dozens of young people to find out what they believe — and why some still practise a faith tradition.

8. Grace Without God: The Search for Meaning, Purpose, and Belonging in a Secular Age

Secular journalist Katherine Ozment offers a personal and critical exploration of how the non-religious find meaning and purpose without faith, and seek out new ways to experience ritual and community.

9. Waking Up: A Guide to Spirituality Without Religion 

New York Times bestselling author and avowed atheist Sam Harris makes a case for the benefits of mindfulness meditation as a way to achieve a spiritual life.

10. Good Without God: What a Billion Nonreligious People Do Believe

Harvard humanist chaplain Greg M. Epstein argues for the merits of living a good life — living well, building community, celebrating tradition and being good — with or without God.

This story was originally published as part of Bokma’s monthly column, “Spiritual but Secular.”