The Sun is a star that many astronomers assume is only worth studying because of its averageness; it’s middle-aged and middle-sized. Its convenient proximity to us means it can act as a testbed for physics research. But we’re too well-schooled in the Copernican principle to view it as ‘special’ in any way.
In contrast, Lucie Green’s huge enthusiasm for the Sun is apparent throughout her book. Her purpose is to convey the current state of knowledge about our neighbourhood star, and the story proper starts with sunspots. As a result of the invention of the telescope at the beginning of the 17th century, Galileo, and other early adopters of this technology, were able to observe dark patches on the surface of the Sun appearing and disappearing on timescales of just a few weeks.