Mexico’s middle class is now the “new majority,” according to the authors of a new, and much-quoted book, “Mexico: A Middle Class Society, Poor No More, Developed Not Yet.” The authors, economist and Mexico’s former undersecretary of Trade, Luis de la Calle, and Luis Rubio, former advisor to Mexico’s secretary of Treasury, write that “Even though there is no consensus on what exactly constitutes the middle class, there is no doubt that a significant portion of the Mexican population behaves and perceives itself as one.” This will surprise many — including many Mexicans — several analysts have noted.