Warped Host and Inclined Disks

I review the connection between truncations in stellar disks and warps in the H I layers in spiral galaxies. The onset of the warps, which are usually present when there is H I beyond the optical extent is abrupt and discrete and starts just beyond the truncation. Inside the truncation disks of galaxies are extremely flat (little deviation from a single plane). Truncations are difficult to see in galaxies that are not edge-on. Latest results show that they can be seen also in inclined/face-on systems at the faintest levels that can be observed, but only when the galaxy does not have a faint, extended stellar halo. Much, but not all of what follows has also been covered in the recent article on Annual Review of Astronomy & Astrophysics by Kruit & Freeman (2011).