Fred Freiberger directed some of the best episodes. It's a fascinating insight into mindless racial hatred and only "bogs down" a bit in the middle. Could have also been written by Dr. Seuss as it brings to mind his fable of "Sneetches with and without stars" (who are better?). Two beings exactly alike in every way except one has a left white face with the right side black and the other is exactly the opposite. One is the master race and one is the slave race. Both have super-powers and can control the Enterprise. You get the idea. All theories are suggested by Spock including nature vs. nurture. Their hated has outlasted the population of their planet. The only writing flaw is their hatred spans thousands of years. Nobody lives than long, except the "Q" maybe! A fitting "1960's episode". Frank Gorshin channels his inner "Kirk Douglas" as he was an amazing impressionist as well. A brilliant performance as "Commissioner Bele" in pursuit of a "filthy-right sided white face" criminal whom he believes caused the uprising on planet Cheron". Now they will battle for eternity, together and forever. The "stock footage" used for the burning of the planet looks suspiciously like the burning of Atlanta from GWTW, don't you think?
Review of Let That Be Your Last Battlefield
