  With increasingly accurate data on RR Lyrae stars we find that the Blazhko
effect may be a rule rather than an exception. However, we still do not know
what is the cause of this mysterious amplitude and phase modulation. In my
talk, I intended to give a glimpse of the properties of Blazhko stars,
presenting recent findings concerning what makes Blazhko stars different from
their non-modulated counterparts. Recent observations of Blazhko stars obtained
from space give some important clues that deserve further exploration.
