What is the difference between Adobe After Effects and Adobe Premiere ?

The title says it all. Why are these programs independent and what are the main differences between them ?

After effects is all about adding additional effects to a video, while Premiere is all about constructing, editing and sequencing the video in the first place.

After Effects is for adding video FX, not for cutting or uploading video to the computer. Premiere is a NLE (Non Linear Editor) that you use to cut your video and add some basic FX. The work flow usaly goes to Premiere first then, when your video is cut, you use After Effects to add the FX.