It’s exciting to read a series of books. Nothing beats the feeling of finishing a great book and diving enthusiastically into its sequel. Beyond entertainment and intellectual nourishment, reading a series is also a point of pride. To finish an entire trilogy, or a five-book or seven-book anthology is a feat of discipline worthy of admiration. Yet as far as book series go, not many can beat Emile Zola’s naturalist collection Les Rougon-Macquart, an ambitious literary cycle made up of twenty separate books.