Seventeen papers from a July 2001 workshop present recent developments in geometric and arithmetic methods for studying mirror symmetry, particularly for counting the number of rational curves on Calabi-Yau threefolds. The contributors explore a toric geometry approach to Calabi-Yau manifolds, Picard-Fuchs differential equations, regulators of Chow cycles, and counting BPS states using holomorphic anomaly equations. Other topics include complex multiplication of black hole attractor varieties, hypergeometric families of Calabi-Yau manifolds, aspects of conformal field theory derived from Calabi-Yau arithmetic, and ordinary Calabi-Yau-3 crystals. No index is provided. Annotation (c) Book News, Inc., Portland, OR (booknews.com)