  In-medium field-theory is applied to different effective models and QCD to
describe mass and isospin effects, finite volume corrections and magnetic
fields in the phase diagram of Strong Interactions, keeping close contact with
experiments and lattice results. Findings range from a technical
nonperturbative solution of the hot and dense regime of a general massive
Yukawa Theory and the computation of the cold and dense chiral surface tension
-- a key quantity for supernovae explosions and compact star structure -- to
the proposal of a novel signature for the QCD critical endpoint in heavy-ion
collisions based on finite-size scaling. The behavior of the deconfining
critical temperature as a function of the pion mass and the isospin chemical
potential is also addressed in an effective model and the description obtained
is in agreement with lattice simulations, in contrast to what is found in
(Polyakov-extended) chiral models. We also discuss the thermodynamics of QCD in
the presence of a (Abelian) magnetic field to two-loop order and a
Functional-Renormalization-Group analysis of relativistic Bose-Einstein
condensation of pions in isospin-dense media.
