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The object of the present study was to compile and unify the basic information on earthquakes in the European area and to present it in a form suitable for further research work on a regional scale. The difficulties involved need not be repeated; they left their negative traces on some sections of the work. The inhomogeneities were sometimes too great to be overcome. Nevertheless, a step forward has been made and the earthquake catalogues 1801 – 1900 and 1901 – 1955 and the seismic maps are ready for further applications. It must be emphasized once again that work of this kind is never completed to the full satisfaction of either the author or the reader. Some uncertainties, doubts or simply errors and gaps always remain and can only be removed by continuous investigation. Our activities are directed towards a more and more accurate determination of the earthquake risk in any arbitrary point of an earthquake zone. At present, we can answer the questions put before us by everyday practice in a relatively modest way. It is evident that a much greater understanding of the physical processes generating earthquakes is needed. This basic research must, however, be combined with a continuous observation of natural phenomena including the realistic information which can be gained from historical records. Earthquakes are caused by long lasting forces within a geological time scale and in some regions not even a 155 year period is sufficient for the estimation of the level of earthquake activity. The recording of very weak shocks with ultra-sensitive seismographs has proved to be not so simple and effective as was assumed and we face the whole problem in only a slightly improved situation compared with 20–30 years ago.