Something possessed me to add the old series, The Invaders, to my Netflix queue a few months ago. I vaguely remembered liking it when I was a kid when it first came out n 1967. So far, I've seen several of the original episodes and, man!, what a great show that was!
It's done by Quinn Martin,the same guys who did The FBI and The Fugitive and it has the same hallmarks: Voiceover intro and ending, "Act I", "Act II", et al.
The premise is that some guy sees an alien spacecraft land and can't convince anyone of it. Meanwhile, while he's checking it out, his home is burned down, the police think he's nuts, and his business partner dies. So now he's on the run hunting them down each episode.
Great show and it's an obvious influence on later shows like the X-Files.