The ability to read is one of the strongest predictors of future success. Although reading can be taught in a classroom, it must be practiced. Michael Jordan can teach you to how to throw the perfect foul line shot, but if you don't ever practice the skill, his instruction is worthless. When students voluntarily read, they practice and enforce what is taught in the classroom. It should be noted that this is more powerful than skill based programs, vocabulary drills and spelling drills.
Text books can never replace the power of a library.
Lance,The Impact of School Library Media Centers on Academic Achievement. Lance, Keith Curry, Lynda Welborn and Christine Hamilton-Pennell. The Impact of School Library Media Centers on Academic Achievement. Hi Willow Research and Publishing. Loertscher, David V., May Lein Ho and Melvin M. Bowie.