In Episode 8 of the Mindful Wealth Podcast, Jonathan and I had the opportunity to interview Kabir Helminski, Sufi Sheikh and spiritual leader. I've been a fan of Kabir's work for a long time. His books Holistic Islam (affiliate link), Living Presence (affiliate link), The Knowing Heart (affiliate link) are a great introductions to the tradition of Sufism specifically, and (in my opinion) sign-posts on the path to spiritual development more generally. I can personally attest to the value of his 99-day program Introduction to Sufism program.