Question: I was a big Lost in Space fan as a kid. Watching reruns, I realized there was a big difference between the evil Dr. Smith from the first episodes and the funny Dr. Smith who came along later. What was the deal with that? — Kevin L., Honolulu, Hawaii

Televisionary: Elementary, you lugubrious lump... you pusillanimous pinhead! (Sorry, my inner Smith got the best of me there, Kevin.)

The simple answer is the one behind so many developments on your favorite shows, both old and new — ratings. As the story goes, actor Jonathan Harris, who played the no-good doctor, and the powers-that-be behind the show, one of many from legendary producer Irwin Allen, realized early on that the truly evil Dr. Smith would wear thin in no time. So though the character was merely sinister when the series launched on CBS in September 1965 — it was his sabotage that got all of them lost in the first place — he soon evolved into the selfish, whiny bumbler we knew and loved so well. And audiences ate it up.

"I am deliciously wicked," Harris gushed to TV Guide in 1966. "I am selfish, self-pitying, pompous, pretentious, peremptory, conniving, unctuous, scornful, greedy, unscrupulous, cruel, cowardly, egotistical and absolutely delightful. The boy [Billy Mumy as young Will Robinson] loves me, but I would gladly sacrifice him to achieve my ends."

Well, somebody had to be sacrificed, and while innocent Will always made it out of Smith's schemes alive, and the remarkably resilient robot (again with the alliteration — the pain, the pain!) bounced back from the doctor's repeated acts of treachery with nary a scratch after repairs, Harris's castmates weren't so lucky. "It isn't so much that he steals the show. It's that they [the producers] give it to him," the late Guy Williams (Zorro), whose Professor John Robinson and brood were supposed to be the focus of Lost in Space when it was created, said of Harris at the time. "We have to — uh, open up the material. Next week's show is better. I have something to do." (Of course, Williams had his own detractors. "He walks on the set combing his hair," complained one of the show's directors. "'Hold it,' he says and we wait. This man is more interested in his hair than his performance.")

But Williams wasn't alone in noticing that Harris had become the alpha male on the set. Harris himself took to strutting (guest star Mercedes McCambridge noted that he "certainly rules the roost") and co-star Mark Goddard, who played the forever grumpy Don West, complained that the show was "lousy with ego."

The fans and critics didn't help matters much, either. On a day when a TV Guide reporter visited the set, a group of kids surrounded Harris while a smiling Williams, ostensibly the hero, walked by unnoticed, losing his grin in the process. TV Guide reviewer Cleveland Amory made it even worse when he pointed out that next to the robot (voiced by Dick Tufeld), Harris was the best actor on the series. "He is responsible almost every week for lousing up outer space with his innate rottenness, and you've got to love him for it," he wrote. That people did. And with his off-the-scale campiness — the scheming, shrieking and foppishly sinister ineptitude — Harris's Smith tried to sell out the robot, young Will and his other Jupiter II shipmates on a weekly basis and helped to earn some respectable ratings in the process.

As often happens, however, the same over-the-top performances that pulled viewers in began to push them away when they tired of the antics. Network bigwigs, many of whom were embarrassed by the show all along — CBS head honcho William Paley despised Lost in Space and wanted it gone the instant its audience turned their backs — took advantage of the ratings decline and a climbing production budget at the end of the third season and cancelled it. (Allen would have the last laugh, though, when the show launched into syndication in 1969 and pulled in a sizable fan base once again.)

Certainly, for all the grousing at the network and on the set, there were those who knew where their bread was buttered. The most gracious of the bunch was probably June Lockhart (Lassie, Petticoat Junction), who portrayed mama Maureen Robinson and gave credit where credit was due. "After all," she admitted, "we probably wouldn't be here at all without Jonathan."