In Lecture 1, I survey the thermodynamics based on quantum
chromodynamics as the fundamental theory of strong interaction
physics. In particular, color deconfinement and chiral symmetry
restoration are elaborated.
In Lecture 2, the phase diagram of strongly interacting matter
is presented and interpreted in terms of hadronic interaction
regimes. For the deconfined region, the possibility of a novel
phase consisting of massive quarks is considered.
In Lecture 3, the spectral analysis of the quark-gluon plasma
through quarkonium dissociation is presented. It is subsequently
applied to the question of QGP formation in high energy nuclear
collisions.
In Lecture 4, the relative abundance of hadron species in high
energy collisions is interpreted in terms of statistical hadronization.
The origin of this phenomenon is then discussed on the basis of
Hawking-Unruh radiation in QCD.