Long-period (LP) and very-long-period (VLP) volcanic events are distinct seismic signals and very different in frequency, waveform and source character from any other earthquake-related tectonic event. While LPs play an important role as a potential forecasting tool, VLPs fill the gap between the classic seismic frequency band and monitoring of ground deformation. VLP signals have been recorded on volcanoes in the last three decades only due to the increased availability of broadband seismic sensors in monitoring networks. We describe the distinct characteristics of LPs and VLPs in order to identify both and provide source models, which are necessary for their interpretation in terms of the underlying volcanic processes. When we describe several procedures and processing steps to extract all the information these important signals contain we focus on applications in an operational monitoring environment rather than on theory. These procedures range from testing seismic moment tensor inversions for sufficiently dense networks to minimal approaches with only a few seismic sensors. We conclude this chapter with a check list for monitoring staff which provides advice regarding the design and deployment of seismic networks as well as the necessary processing steps to extract maximum information.