"The Mark of Gideon" takes Trek where it has famously gone before, exploring serious social issues more or less head on, this time approaching overpopulation with overtones towards the sanctity of life and euthanasia. The planet Gideon is horrifically overcrowded yet its inhabitants cling to life so fiercely they must literally send out for lethal disease.

Not yet a member of the UFP, Gideon is tirelessly caught up in "a tissue of lies" disguising the wretched actual conditions of their shield protected former paradise. (Probably a whole boxful, amid other problems suggested by Odona's task to inspire the younger Gideonites to die. Why the young? Why not Hodin for the old?) If Gideon is considered as an entire planet of Flints (i.e. near immortals) it would be interesting to see what social structures emerge from the "Odona experiment."

Both Federation and Starfleet bureaucracies are unflatteringly lit, dancing delicately around the diplomacy of the situation. Why? Of course it can't be easy to shield an entire planet; that represents powerful technology. For that matter it can't be simple to build a replica of a starship, especially on a planet teeming with people. (Based on what? A few technical manuals?) The very creepy shot of a restless bustling crowd is an iconic Trek image, begging the question regarding a source of food for that sea of faces. Or the disposal of their waste. Actually if those two questions answer each other it might be best not to know. Like Soylent Green only worse!

Sharon Acker shines as the beautiful "guinea pig" Odona, convincingly concealing the ruse. David Hurst annoys excellently as Hodin, parsing Spock's responses hoping to get away with his captain-napping, but mistaking the Enterprise crew's urge to recover their captain. Trek veteran Gene Dynarski enjoys a moment as the bald-pated Krodak. Similarly welcome is Richard Derr as the "arbitrary" Admiral Fitzgerald around whom Spock wends a logical, implacable path even as McCoy needles his obsequiousness towards the obviously lying Gideon council. Scotty also gets good time as an "excitable repairman," and Kirk consistently drives himself to not only investigate the mystery but in his angry, adamant retort to Odona's plea, to never "be content."

New "empty" camera angles further redeem the overall effect as does moving (re)use of earlier scores. It does suffer a bit from makeup on the Gideon council, and the title may not be the best (supposedly a poor biblical pun, with Kirk as the "mark" in a con?), but this episode is far from the worst.