I am enjoying Roger Ekirch’s fascinating book At Day’s Close: Night in Times Past. He describes the night as “the forgotten half of history”, and sets out to demolish the idea that night is simply a negative – the flip-side of day, when everything happens.

It’s a thick book – 450 pages – but Ekirch’s scholarship and encyclopaedic research more than justify the length. He covers every aspect of night, from the dangers of being stabbed by crowds of drunken “gallants” (upper-class rowdies) in 17th century London to the problems faced by escaping slaves in colonial America.

A running theme in the book is that conventions were relaxed, and the rigid structures of society loosened, as soon as night fell. Before the invention of gas and electric lighting, masters could not see what their apprentices were up to, nor wives their husbands. Freedom descended on cities and villages alike, and those who were used and abused by day could take their revenge without the risk of discovery.

There are some surprising insights: Ekirch reminds us that in times of persecution, religious groups held meetings at night to escape detection. He gives the example of the Adamites, who were active in England in the mid-17th century. They eccentrically evoked the innocence of the Biblical Garden of Eden by worshipping without clothes.

I originally bought At Day’s Close because I needed some information about fear of the dark for a book I am writing for Collins, but it has proved to be far more entertaining than I ever thought possible.