  This text is a mostly self-contained textbook-like introduction to classical
and modern Iwasawa Theory in Spanish language. It grew out of notes for a
course that the authors gave at the annual conference of the Mexican
Mathematical Society (SMM) in 2018. It covers some preliminaries from algebraic
number theory and profinite algebra, the theory of the Iwasawa algebra and its
modules, results about class groups in $\mathbb{Z}_p$-extensions, $p$-adic
$L$-functions for Dirichlet characters and their various constructions (along
with some complex theory of $L$-functions), the cyclotomic main conjecture in
different formulations together with its most important implications, and a
chapter about generalizations outlining logarithmic Iwasawa theory and
generalizations of the Main conjecture to elliptic curves, motives and the
ETNC. The text includes references and detailed proofs, some of which are not
available in the standard literature, and is accessible for anyone with basic
knowledge of algebra and some algebraic number theory.
