Before each school year, the Ministry of Education publishes a list of approved textbooks, from which teachers will choose the ones they will use in class. For the 2017-2018 school year, the list is 30 pages long. There is big money in school books, explains a publisher who wants to remain anonymous. "Getting on the list is the Holy Grail, and no holds are barred. Imagine a little, it's a huge market, more than 5 million students! Everyone wants their share of the pie: authors, publishers, printers or distributors, even if the methods they use are not always legal.”