Studies on the solution structure dynamics of RNA/DNA are becoming crucially important. The phenomena of SSCP (single-strand conformation polymorphism), microRNA dynamics in a cell, and others can be related to the conformational changes of single-stranded (ss) RNAs/DNAs in solution. These molecule, which no longer forms a helix, can adopt many different conformations in solution. What are typical conformations of these molecules and what factors govern their conformational space? To answer these important biological questions we need to explore the three broad areas: 1) How does the shape of DNA and its surroundings mutually influence each other? Can we determine their existing relationship? 2) How is the DNA sequence related to its structure? Can we determine the structurally important residues based on the DNA sequence? 3) How is the DNA sequence related to its function? Can we determine the functionally important residues based on the DNA sequence? These and similar questions which require the knowledge of accurate molecular conformations have been studied in this book in an understandable fashion and in order to gain insight into the structure dynamics of DNA in solution.