The Book of Shahab is a spiritual and philosophical work that asks one radical question: what if every great faith tradition has been pointing at the same light from different windows? Drawing on the sacred texts of Zoroastrianism, Judaism, Christianity, Islam, Buddhism, Hinduism, and Sikhism - and grounding each insight in modern science, neuroscience, and psychology - the book presents a universal spiritual path called Shahabism, built on a single ancient foundation: good thoughts, good words, good deeds. At its heart are the Four Circles of Goodness: be good to yourself, your family, your community, and your world. This is not a rejection of existing faiths but a joyful recognition of their shared core. The book explores how one God has been known by many names, how science and spirituality illuminate rather than contradict each other, and how the daily practice of goodness is both the most ancient and most modern path to a meaningful life. The Book of Shahab offers practical guidance for daily living alongside deep theological reflection - never demanding conversion, only an open mind and a willing heart. The light is one. The windows are many.