There has recently been a dramatic renewal of interest in the subjects of hadron spectroscopy and charm physics. This renaissance has been driven in part by experimental reports of D-0(D) over bar (0) mixing and the discovery of narrow D-sJ states and a plethora of charmonium-like XY Z states at the B factories, and the observation of an intriguing proton-antiproton threshold enhancement and the possibly related X(1835) meson state at BESII. At the same time, lattice QCD is now coming of age, and we are entering a new era when precise, quantitative predictions from lattice QCD can be tested against experimental measurements. For example, the High Precision QCD (HPQCD) and United Kingdom QCD (UKQCD) collaboration's recent high-precision, unquenched calculation of f(D+) = 208 +/- 4 MeV has been found to agree with the CLEO-c collaboration measurement of f(D+) = 223 +/- 17 +/- 8 MeV - a precision level of similar to 8%. Intriguingly, this agreement does not extend to f(Ds), where the HPQCD + UKQCD result f(Ds) = 241 +/- 3 MeV is more than three standard deviations below the current world average experimental value f(Ds) = 276 +/- 9 MeV. Precision improvements, especially on the experimental measurements, are called for and will be of extreme interest. The BES-III experiment at BEPCII in Beijing, which will start operation in summer 2008, will accumulate huge data samples of 10 x 10(9) J/psi, 3 x 10(9) psi(2S), 30 million D (D) over bar or 2 million DS+DS--pairs per running year, respectively, running in the tau-charm theshold region. Coupled with currently available results from CLEO-c, BES-III will make it possible to study in detail, and with unprecedentedly high precision, light hadron spectroscopy in the decays of charmonium states and charmed mesons. In addition, about 90 million D (D) over bar pairs will be collected at BES-III in a three-year run at the psi(3770) peak. Many high precision measurements, including CKM matrix elements related to charm weak decays, decay constants f(D+) and f(Ds), Dalitz decays of three-body D meson decays, searches for CP violation in the charmed-quark sector, and absolute decay branching fractions, will be accomplished. BES-III analyses are likely to be essential in deciding if recently observed signs of mixing in the D-0(D) over bar (0) meson system are actually due to new physics or not. BES-III measurements of f(D+) and f(Ds) at the similar to 1% precision level will match the precision of lattice QCD calculations and provide the opportunity to probe the charged Higgs sector in some mass ranges that will be inaccessible to the LHC. With modern techniques and huge data samples, searches for rare, lepton-number violating, flavor violating and/or invisible decays of D-mesons, charmonium resonances, and tau-leptons will be possible. Studies of tau-charm physics could reveal or indicate the possible presence of new physics in the low energy region. This physics book provides detailed discussions on important topics in tau-charm physics that will be explored during the next few years at BES-III. Both theoretical and experimental issues are covered, including extensive reviews of recent theoretical developments and experimental techniques. Among the subjects covered are: innovations in Partial Wave Analysis (PWA), theoretical and experimental techniques for Dalitz-plot analyses, analysis tools to extract absolute branching fractions and measurements of decay constants, form factors, and CP-violation and D-0(D) over bar (0)-oscillation parameters. Programs of QCD studies and near-threshold tau-lepton physics measurements are also discussed.