LEED Green is an initiative by the USGBC or United States Green Building Council. They are the ones who develop the LEED Green system and ratings for the different buildings based on their performance towards reducing environmental impacts. GBCI or Green Business Certification Inc. is the one develop the testing programs and certifications for certifying the buildings and people. 

There are primarily two certifications that one can earn. The LEED Green Associate and then followed by the LEED Accredited Professional in the field of New Building, New Construction, Existing Building Operation and Maintenance etc. 
The study material that current exists is version 4.1 and now moving towards the version 5.0 Any individual who is wanting to work in the field of Construction Engineering Architecture and Landscape Design and any other practices related to civil and environmental engineering is encouraged to have these certification as a commitment towards the environment protection, sustainability and growth. People , Planet , Profit being the triple bottom line of USGBC encourages to enlighten people with the benefits of certifying the buildings towards LEED Certified/Silver/Gold or Platinum ratings in the near future.