In this contribution I give an overview on detections of X-ray obscuration in AGN. First I present the discovery of obscuration in NGC 5548. In particular the simultaneous presence of lowly ionized, high column density X-ray absorption together with the presence of broad, deep absorption troughs in the UV allowed us to obtain a consistent picture of what is happening during this process. I will indicate some of the challenges in the spectral modeling of these data. Obscuration has also been found in a couple of other sources, and I will briefly compare the similarities and differences between the obscuration in these sources. I finish with some open questions. like:
- what is the difference between obscuration and an eclipse?
- What are the timescales for obscuration: weeks, years, centuries?
- where is the obscuring stream originally born and how?
- is there a connection between certain accretion disk behavior and the obscuration?
- What fraction of the AGN continuum is covered by the obscuration?