 The new cyclic cosmology of Steinhardt and Turok develops ideas from string theory to describe a universe without inflation going through an endless sequence of cycles—in which case, the big bang is not the beginning of time (Steinhardt and Turok 2007). In this respect the model is similar to the steady-state model, and Steinhardt and Turok have indeed described it as a “remarkable reincarnation” of Hoyle’s old theory. Although the new cyclic model has attracted a fair amount of attention, it is not widely accepted. Nor is this the case with the pre-big-bang bouncing cosmology advanced by Gabriele Veneziano and Maurizio Gasperini on the basis of string theory. According to the pre-big-bang model the universe is not only eternal into the future, it is also eternal into the past, the two cosmic phases (contracting and expanding) being separated by a non-singular big bang.