ScanSAR data provides wide swath coverage and at fast revisit times at the expense of resolution. Moreover, the ENVISAT/ASAR alternating polarisation mode uses the burst-mode acquisition to map the scene quasi-parallel in two polarisations. Both modes are also attractive for interferometric applications, e.g. efficient topographic mapping of large areas and monitoring of large scale motions. A single-pass ScanSAR interferometer was flown during the 11-day Shuttle Radar Topographic Mission (SRTM). Repeat-pass ScanSAR data are routinely available from RADARSAT-1 and ENVISAT/ASAR and the coming RADARSAT-2 and ALOS/PALSAR mission will also provide ScanSAR imaging modes. This thesis provides a complete description of burst-mode and ScanSAR signal characteristics, algorithms for interferometric processing, and options for the efficient utilisation of the wide-swath data. In the course of the examinations the following problems are addressed: Doppler centroid estimation, azimuth scanning pattern synchronisation, common band filtering and resampling in the presence of high squint, beam alignment, and interferogram formation. A new fast time-variant interpolator for burst-mode data is introduced and tested. Several processing options are described that exploit the flexibility of burst-mode and ScanSAR data. Hence, possibilities are available for prototype systems that are most conveniently integrated into existing strip-map processors and for systems that allow data processing in operational fashion. A prototype processor that makes efficient use of the burst-mode and ScanSAR data properties was implemented and tested using a RADARSAT-1 ScanRAR Narrow data set. In this way, RADARSAT-1 repeat-pass ScanSAR interferometry is demonstrated. The generated digital elevation model has quality in the order or better than DTED-1. Moreover, after interferometric processing the ScanSAR interferogram resembles a course resolution strip-map interferogram and, hence, possibly all applications of SAR interferometry may benefit from ScanSAR data. In particular, the data is favourable for those applications gaining from the wide swath extend, the fast revisit times, or from the increase in information provided with the alternating polarisation mode, as on ENVISAT/ASAR.