The Time Traveller’s Guide to Elizabethan England, by Ian Mortimer
The clue is in the title. This is a fascinating and well researched read about everyday life in Elizabethan England, with the conceit that it’s aimed at anyone who might be thinking of travelling back there, not just describing things but drawing attention to the differences and dangers of assuming you will just fit in. The kind of thing any sf author ought to bear in mind, in fact. My favourite bit: the formula for a popular perfume that anyone can make at home, which “provided your breath be not too valiant” will have you smelling “sweet as any lady’s dog.”