Cosmological observations have shown that the standard, hot Big Bang cosmology must have been preceded by a drastically different epoch in the very early universe. The leading candidate paradigm for this epoch is inflation: a period of accelerated expansion in the early universe. Inflation can be achieved with rather simple theoretical ingredients, but the microscopic origin of inflation, and what we can learn about high-energy physics from cosmological observations, remain important outstanding questions. This project explores several theoretical and phenomenological questions within inflationary physics, including how we can learn about the particle spectrum at high energies from imprints in the Comis Microwave Background and the distribution of matter on cosmic scales.