There are numerous helpful books about mindfulness. The list below is just a starting point.
Brach, Tara. True Refuge: Finding Peace and Freedom in Your Own Awakened Heart. NY: Bartram, 2013.
Brach, Tara. Radical Acceptance: Embracing Your Life with the Heart of a Buddha. NY: Bartram, 2004.
Chodron, Pema. How to Meditate: A Practical Guide to Making Friends with Your Mind. CO: Sounds True, 2013.
Chodron, Pema. Any of her books.
Germer, Christopher and Sharon Salzberg. The Mindful Path to Self-Compassion: Freeing Yourself from Destructive Thoughts and Emotions. The Guiford Press, 2009.
Gunaratana, Ven. Henepola. Mindfulness in Plain English.
Kabat-Zinn, Jon. Full Catastrophe Living: Using the Wisdom of Your Body and Mind to Face Stress, Pain and Illness. NY: Bartram, 2013.
Karmapa, Ogyen Trinley Dorjey. Interconnected: Embracing Life in Our Global Society. MA: Wisdom Publications, 2017.
Orsillo, Susan and Lizabeth Roemer. The Mindful Way Through Anxiety: Break Free from Chronic Worry and Reclaim your Life. The Guiford Press, 2011.
Rinpoche, Yongey Mingyur and Eric Swanson. Joy of Living: Unlocking the Secret and Science of Happiness. Harmony, 2008.
Hanson, Rick. Just One Thing: Developing a Buddha Brain One Simple Practice at a Time. New Harbinger, 2011.
Williams, Mark, John Teasdale Zindel Siegal and Jon Kabat-Zinn. The Mindful Way Through Depression: Freeing Yourself from Chronic Unhappiness. The Guiford Press, 2011.