Intro -- Contents -- Preface -- Extremal geometries -- Extremal Riemann surfaces with a large number of systoles -- On arithmetic genus 2 subgroups of triangle groups -- Some lattices obtained from Riemann surfaces -- Jacobian of the Picard curve -- Fermat's quartic curve, Klein's curve, and the tetrahedron -- Riemann surfaces admitting large automorphism groups -- The splitting of some Jacobi varieties using their automorphism groups -- Number theory, theta identities, and modular curves -- Uniformization of some quotients of modular curves -- Teichmüller disks and Veech's F-structures -- On the geometry and spectral asymptotics of degenerating hyperbolic three manifolds -- Differential equations for the quadratic periods of abelian differentials -- Zeta functions on S2 -- A minimum problem for heat kernels of flat tori.