Abstract : The University of Florida (UF) and Florida Institute of Technology (FIT) have completed a one-year, exploratory (seedling) program (March 25, 2008 to August 22, 2009, DARPA Grant HR-OO1-08-1-088) that has examined various aspects of lightning initiation and propagation including the role of X-rays, gamma rays, and cosmic rays in the initiation and propagation of lightning and in the phenomenology of thunderclouds. The experimental portion of the research has taken place at the International Center for Lightning Research and Testing (ICLRT) in north-central Florida. The deliverables of the exploratory grant include the material described in the journal papers listed in this report. This material additionally serves to demonstrate the UF-FIT experimental and theoretical capabilities in the subject area.