Inflation is today believed by essentially all the scientific community to be the initial stage in the evolution of the Universe, giving the seeds to what then later develops into structures such as galaxies and human beings. All other known theories have today been observationally excluded, leaving inflation as our currently best understanding of the early Universe.
Linde describes in glorious detail all the physics needed for the understanding of inflationary cosmology, such as symmetry breaking (restoration) and phase transitions, and he describes various worked through scenarios, but the description is fairly technical and a strong background in mathematic is necessary. The book is intended for scientists and serious students, and non-scientists will need a good portion of patience to follow all the technical explanations.