  The number of publications considering Narrow-Line Seyfert 1 galaxies has
increased dramatically in recent years. Especially after the launch of the
X-ray missions ROSAT and ASCA, Narrow-Line Seyfert 1s have become very popular.
In these proceedings I will give an overview of how they are distributed over
the electromagnetic spectrum. I will describe what we know about them at radio,
infrared, optical, and X-ray bands, and how they differ and how they are
similar to Broad-Line Seyfert 1s. Finally I will introduce a method to find
them with high probability.
