This work provides the current theory and observations behind the cosmological phenomenon of
dark energy. The approach is comprehensive with rigorous mathematical theory and relevant
astronomical observations discussed in context. The book treats the background and history
starting with the new-found importance of Einstein's cosmological constant (proposed long ago)
in dark energy formulation as well as the frontiers of dark energy. The authors do not
presuppose advanced knowledge of astronomy and basic mathematical concepts used in modern
cosmology are presented in a simple but rigorous way. All this makes the book useful for both
astronomers and physicists and also for university students of physical sciences.
