Complex sentence: The first two volumes were edited by Isaac Asimov; due to Asimov's death in April 1992, the third volume was edited by Connie Willis and the fourth was edited by Greg Benford.
Split into simpler sentences: The first two volumes were edited by Isaac Asimov. Due to Asimov's death in April 1992, the third volume was edited by Connie Willis and the fourth by Greg Benford.