The survey above provides some idea of the vast array of sources and kinds of data that have been brought to bear in the effort to understand dreaming since the beginning of the laboratory era of sleep research.
Dreams have been systematically collected in the laboratory under many different conditions, and experimental manipulations of dreams and of REM sleep have been performed.
The relationship between the physiology of REM sleep and dreaming has been scrutinized.
Recent rapid developments in the neurosciences have led to impressive advances in knowledge of the functioning of the brain during REM sleep and dreaming.
At the same time, understanding of dreaming derived primarily from the intensive exploration of individual dreams in their subjective context retains an essential place. At this current point in the history of the field, there are widely differing views concerning how dreams should be seen in light of all the available data. We can look forward to continued stimulating growth in this field in the coming years.