Harry's War of the Worlds  Harry Turtledove's 'alternate
histories' have a noble lineage, with echoes in works as popular
as this summer's movie blockbuster 'Independence Day' copyright
1996, Jerusalem Report   In a 1993 novel called The Guns of the
South, writer Harry Turtledove explored what might have
transpired had 21st-century Afrikaner reactionaries used a time
machine to supply Robert E. Lee's nearly defeated Southern
armies with Soviet-style assault rifles. That exercise, though,
was just a warm-up for his latest effort, a sweeping tetralogy
of quasihistorical extrapolations called "Worldwar," a series of
science fiction novels that ponders how the world of 1942 might
have developed had a race of technologically advanced aliens
suddenly invaded the earth. The first book was published in
1994, and the fourth and final volume is due out from Del Rey in
December. Turtledove is Jewish, and the effect the alien
invasion has upon the Holocaust becomes one of the series'
central concerns. For instance, the f