  We discuss general thermodynamic properties of molecular structure formation
processes like protein folding by means of simplified, coarse-grained models.
The conformational transitions accompanying these processes exhibit
similarities to thermodynamic phase transitions, but also significant
differences as the systems that we investigate here are very small. The
usefulness of a microcanonical statistical analysis of these transitions in
comparison with a canonical interpretation is emphasized. The results are
obtained by employing sophisticated generalized-ensemble Markov-chain Monte
Carlo methodologies.
