The paper by Fien Apers, Joseph P. Conlon, Edmund J. Copeland, Martin Mosny, and Filippo Revello explores stringy cosmologies between the end of inflation and the commencement of the Hot Big Bang. This period, which can cover half the lifetime of the universe on a logarithmic scale, involves extended kination, tracker, and moduli-dominated epochs with significant trans-Planckian field excursions. Conventional effective field theory is insufficient to control these epochs, necessitating a stringy completion for a consistent analysis. Perturbation growth in these cosmologies is significantly enhanced compared to conventional cosmologies, leading to radical changes in Standard Model couplings. The authors outline potential applications to baryogenesis, dark matter, and gravitational wave production. The paper is structured into sections covering the background cosmology, cosmological perturbations, and the implications for particle cosmology and open directions. Key topics include the evolution of the universe through kination, the transition to radiation domination, the tracker solution, moduli domination, and reheating. The authors provide detailed analytic descriptions of these epochs and analyze the propagation of fluctuations within this modified cosmology, focusing on the volume field.The paper by Fien Apers, Joseph P. Conlon, Edmund J. Copeland, Martin Mosny, and Filippo Revello explores stringy cosmologies between the end of inflation and the commencement of the Hot Big Bang. This period, which can cover half the lifetime of the universe on a logarithmic scale, involves extended kination, tracker, and moduli-dominated epochs with significant trans-Planckian field excursions. Conventional effective field theory is insufficient to control these epochs, necessitating a stringy completion for a consistent analysis. Perturbation growth in these cosmologies is significantly enhanced compared to conventional cosmologies, leading to radical changes in Standard Model couplings. The authors outline potential applications to baryogenesis, dark matter, and gravitational wave production. The paper is structured into sections covering the background cosmology, cosmological perturbations, and the implications for particle cosmology and open directions. Key topics include the evolution of the universe through kination, the transition to radiation domination, the tracker solution, moduli domination, and reheating. The authors provide detailed analytic descriptions of these epochs and analyze the propagation of fluctuations within this modified cosmology, focusing on the volume field.