Alan Guth of MIT will be speaking at this special Nobel Colloquium. The abstract is as follows: I will trace the enormous progress in cosmology in the past century, from Einstein's static universe of 1917 to the modern $\Lambda$CDM (cosmological constant $\Lambda$ + cold darkmatter model. Particular emphasis will be placed on the role of Jim Peebles, one of this year Nobel Laureates, in bringing about this transition. Highlights will include the cosmic microwave background, big bang nucleosynthesis, inflation, cold dark matter, and cosmic acceleration.