Ever since he was a boy, picking onions and working on roofs to help support his family, Benjamin Alire Sáenz had the uncanny feeling that he was living in two worlds, not one.

Mr. Sáenz spent nearly his entire life on la frontera, or the borderlands. Raised on a farm outside Las Cruces, New Mexico, he eventually settled in El Paso, 40 miles to the south, where he won widespread acclaim as a poet and novelist, writing books that used the U.S.-Mexico border as a backdrop for tender explorations of love, redemption and the human condition.