Topics in Cosmology—Clearly Explained by Means of Simple Examples

This is a very comprehensible review of some key issues in modern cosmology. Simple mathematical examples and analogies are used, whenever available. The starting point the well-known Big Bang cosmology (BBC). We deal with singularities appearing this theory discuss ways to remove them. Next, before introducing inflationary paradigm by means clear examples, we horizon flatness problems old BBC model. then consider current cosmic acceleration and, as procedure both periods unified way, study quintessential inflation. Finally, reheating stage universe via gravitational particle production, which took place after inflation ended, discussed terms, involving so-called α-attractors context