(NEW YORK POST) Now on sale at Amazon and Barnes & Noble: 50 shades of gross.

The nation’s dominant booksellers are peddling a raft of raunchy online books depicting incest, rape and bestiality — and some critics charge the retailers would rather hide the fast-proliferating and profitable filth than get rid of it.

Following the sleeper success of “Fifty Shades of Grey,” smutty e-books have engulfed Amazon and B&N’s sites, many of them crossing a line well beyond the sadomasochism and bondage scenes in E.L. James’s kinky trilogy.

Note: Read our discussion guidelines before commenting.