  We present a study of the X-ray properties of several NLS1 galaxies, focusing
on their warm absorbers. In the first part, we discuss properties of dusty and
dust-free warm absorbers in NLS1s, and study their potential contribution to
high-ionization optical iron lines. In the second part, we summarize our work
on the exceptional spectral variability of the NLS1 galaxy RX J0134.3-4258
(from Gamma about -4.4 in the ROSAT all-sky survey observation, to about -2.2
in our subsequent pointed observation).
