The Quaternary covers the last 2.5 million years in Earth's history. This unique period is well known for a record of oscillating climatic parameters. Fluctuating climates are reflected in peatbog profiles. Paleoecological studies using plant macrofossils, like bryophyte remains, have an important role in the reconstruction of past hydrological changes in lakes and peatbogs. Plant macrofossil analysis has been used most frequently in the oceanic regions of Europe, where the moisture gradient is reflected clearly in different Sphagnum taxa. This book discusses research in regard to the paleoecology of peatlands, with a particular emphasis placed on Hungary.