Available in English for the first time, Joaquim Amat-Piniella's searing Catalan novel, K.L. Reich, is a central work of testimonial literature of the Nazi concentration camps. Begun immediately after Amat-Piniella's liberation in 1945, the book is based on his own four-year internment at Mauthausen.

"When the war is over, remember all this. Remember me," implores one of the book's characters on his deathbed, and it is this call to bear witness that Amat-Piniella takes up in his account of the Spanish Republican fighters who were exiled in France at the end of the Spanish...