Well, light some incense and bang that tambourine! "Reach Out of the Darkness" is one of the canonical Flower Power songs, almost to the point of being a stereotypical parody of itself. It was written by Jim Post of the husband-and-wife duo Friend & Lover - Cathy Post being the other half. It is also Friend & Lover's sole hit, although Jim Post has had a moderately successful performing career since.
And Cathy? They divorced. Jim's next spouse, Janet, moved in with him in Galena, Illinois.
Media to use this song includes a 1999 TV commercial for a Milton Bradley game, in the Robert Downey Jr., Kiefer Sutherland, and Winona Ryder film 1969 (released in 1988), and in an episode of the ABC TV series Night Stalker. This last was a remake of the mid-'70s TV series Kolchak: The Night Stalker, which was a kind of X-Files predecessor with a lone detective hunting down vampires and werewolves.
Note that Jim appears to be singing "freak out" while Cathy is singing "reach out." This has fueled an urban legend that Jim wrote the song while tripping on LSD and had to tone the lyrics down before the song could be released. Maybe so or maybe not; urban legends have it that everything in the '60s was done under the influence of LSD, including the Apollo moon missions. It's enough to make you think that LSD itself is just a myth. It wouldn't be a bit surprising if it turned out that it was.