Night-night is easy!
When nights with your baby are sleepless. When everybody asks you “Is she a good baby? Does she fall asleep?” regardless of the bags under your eyes. When all information is a bit confused (wouldn't she simply eat and sleep?) and your grandmother, aunt and neighbour blame you because your little one has difficulty in falling asleep, does not sleep overnight and by himself. Well, it is time you sat down and red this book.
Ps: It will also be useful to prevent all the problems above