Complex sentence: Alfred Elton van Vogt (April 26,1912--January 26,2000) was a Canadian-born science fiction author regarded as one of the most popular, influential and complex practitioners of the mid-twentieth century, the genre's so-called Golden Age.
Split into simpler sentences: Alfred Elton van Vogt (April 26,1912--January 26,2000) was a Canadian-born science fiction author. He is regarded as one of the most popular, influential and complex practitioners of the mid-twentieth century, the genre's so-called Golden Age.