 Zondervan claims that its "NIV Study Bible" has six million in distribution and that it is the world's best selling study Bible.The "ESV Study Bible" is a recent addition which sold well in its pre-release phase, in the fall of 2008.In recent times, study Bibles focusing on specific aspects of the Biblical message, have appeared, such as "The Green Bible", an English version of the "New Revised Standard Version Bible" (originally published by Harper Bibles on October 7, 2008), which focuses on environmental issues and teachings.