Expansions of Knowledge by Chaim Vital is the companion book of Explanation of Knowledge (Derush Ha-Daat), which contains the recording of the teachings by the Arizal concerning his overall system. Expansions of Knowledge further details the Lurianic system and includes over 30 additional unique drawings. The uniqueness of this book relies in the explanations about writing the Name of YHWH and Holy Names in general. The Shofer (scribe) as well as the practicing kabbalist must know the deep significance behind the mere act of writing, for they need to channel the proper "light" to make the word alive. Holy Names do not work if they are not animated by the proper Intentions and Prayers. Indeed, they can cause harm, if used improperly.