Discovery & Depth
  In the United States, the National Science Foundation (NSF), anticipating the no growth in funding, has commissioned a review of NSF-funded astronomy assets with the goal of determining how to best allocate funding for this decade. Inputs from members of the US community were sought. It is a matter of simple arithmetic that for a fixed level of funding many significant aspirations of Astro2010 cannot be met. Here, accepting the boundary conditions posed above, I have focused on fields centered on optical astronomy which offer the best opportunity for progress in this decade and thus offer the highest cost-benefit ratio. Readers may profit from reading the first seven sections. 
S. R. Kulkarni
astro-ph.IM astro-ph.CO