From Brussels to Saint James of Compostela, Patrick Burensteinas, alchemist, who is also a scientist, explains the meaning of the Magnum Opus and the techniques leading to the Philosopher’s Stone.The different stages of his work in laboratory reproduce the 7 steps of an initiatory journey. A search which concerns all of us. During almost two thousand years, Alchemy had a great impact in our life, marking our thoughts in the scientific, cultural or philosophical way.