The discussion revolves around the book "Relativistic Cosmology" by George F. R. Ellis, Roy Maartens, and Malcolm A. H. MacCallum. Participants express interest in the book's suitability for beginners in cosmology, particularly for those who already have a background in General Relativity (GR). There is a mention of an Amazon review, which is noted to be unhelpful. The key question is whether this book can serve as a starting point for learning cosmology, with the consensus leaning towards its potential usefulness for readers familiar with GR.