  Topological defects are ubiquitous in condensed-matter physics but only
hypothetical in the early universe. In spite of this, even an indirect evidence
for one of these cosmic objects would revolutionize our vision of the cosmos.
We give here an introduction to the subject of cosmic topological defects and
their possible observable signatures. Beginning with a review of the basics of
general defect formation and evolution, we then focus on mainly two topics in
some detail: conducting strings and vorton formation, and some specific
imprints in the cosmic microwave background radiation from simulated cosmic
strings.
