This first of two bound volumes present the proceedings of the conference, Complex Analysis, Dynamical Systems, Summability of Divergent Series and Galois Theories, held in Toulouse on the occasion of J.-P. Ramis' sixtieth birthday. The first volume opens with two articles composed of recollections and three articles on J.-P. Ramis' works on complex analysis and ODE theory, both linear and non-linear. This introduction is followed by papers concerned with Galois theories, arithmetic or integrability: analogies between differential and arithmetical theories, $q$-difference equations, classical or $p$-adic, the Riemann-Hilbert problem and renormalization, $b$-functions, descent problems, Krichever modules, the set of integrability, Drach theory, and the VI${}^{{th}}$ Painleve equation. The second volume contains papers dealing with analytical or geometrical aspects: Lyapunov stability, asymptotic and dynamical analysis for pencils of trajectories, monodromy in moduli spaces, WKB analysis and Stokes geometry, first and second Painleve equations, normal forms for saddle-node type singularities, and invariant tori for PDEs. The volumes are suitable for graduate students and researchers interested in differential equations, number theory, geometry, and topology.