A prison advocacy group is suing the Texas prison system over prisoners' rights to order two books on prison conditions and the American criminal justice system.

Texas officials have blocked prisoner access to two books: Women Behind Bars: The Crisis of Women in the U.S. Prison System, by journalist Silja J.A. Talvi and Perpetual Prisoner Machine: How America Profits from Crime by Joel Dyer. Prison Legal News, the distributor of the books, filed a federal lawsuit against the Texas Department of Criminal Justice last week, arguing that the state has denied prisoners their constitutional rights.

But the state says it isn't banning the books because they're critical of the system - officials claim they blocked the books because they're too graphic. In fact, descriptions of sexual assault in the two books are critical to tell the story of a prisoner's life and to address prison conditions. Neither are remotely gratuitous.

Send a letter below to Texas Dept. of Criminal Justice Director Brad Livingston, urging him to reverse the ban.