The Extreme-ultraviolet Imaging Telescope (EIT) is a key instrument on the SOHO mission designed to capture wide-field images of the solar corona and transition region, up to 1.5 solar radii above the solar limb. It uses multilayer-coated optics to select spectral emission lines from Fe IX (171 Å), Fe XII (195 Å), Fe XV (284 Å), and He II (304 Å), providing temperature diagnostics from 6×10⁴ K to 3×10⁶ K. The telescope has a 45×45 arcmin field of view and 2.6 arcsec pixels, offering approximately 5 arcsec spatial resolution. EIT will provide global insights into coronal plasma and the cooler, turbulent atmosphere beneath, enabling comparative analysis with ground-based and SOHO observations. EIT's images in He II provide sensitivity to solar structures an order of magnitude lower in temperature than those from the Soft X-ray Telescope (SXT), while maintaining overlap in the 0.6 to 3 MK range. If plans are realized, EIT and SXT operations will overlap for up to 18 months, allowing comparative analysis of their images. EIT's position at the L1 Lagrangian point ensures data continuity without interruption from Earth occultations, enabling access to a frequency domain in dynamical analyses previously inaccessible due to data gaps. EIT is a Ritchey-Chretien telescope with four multilayer-coated quadrants, each tuned to a specific wavelength band. The telescope uses a back-illuminated CCD with enhanced EUV quantum efficiency, cooled to -80°C. The CCD is automatically registered for the four passbands, and a filter wheel blocks long wavelength solar emission. The EIT's performance is supported by a dedicated electronics box (LEB), sharing a combined telemetry rate of 5.2 Kbps with LASCO. EIT's operations are integrated with LASCO, allowing for flexible and coordinated observations. The EIT's multilayer optics and filters are designed to optimize performance across different wavelength bands. The CCD quantum efficiency is calibrated to ensure accurate data collection, and flat-field calibration is used to correct spatial non-uniformities. The effective areas of each quadrant are determined by mirror reflectivities, filter transmissions, and the CCD's efficiency. EIT's operational modes include full-disk observations, selected areas mode, onboard desaturation, and coordinated observing programs with CDS and SUMER. It is operated from the Experimenters' Operations Facility (EOF) and uses planning tools to schedule scientific objectives. Routine operations include full-field images in all four EUV bandpasses, while real-time operations allow for flexibility in target selection. Data compression is used to reduce the data volume, with ADCT compression providing up to a 10:1 compression factor. EIT's versatility allows it to study aThe Extreme-ultraviolet Imaging Telescope (EIT) is a key instrument on the SOHO mission designed to capture wide-field images of the solar corona and transition region, up to 1.5 solar radii above the solar limb. It uses multilayer-coated optics to select spectral emission lines from Fe IX (171 Å), Fe XII (195 Å), Fe XV (284 Å), and He II (304 Å), providing temperature diagnostics from 6×10⁴ K to 3×10⁶ K. The telescope has a 45×45 arcmin field of view and 2.6 arcsec pixels, offering approximately 5 arcsec spatial resolution. EIT will provide global insights into coronal plasma and the cooler, turbulent atmosphere beneath, enabling comparative analysis with ground-based and SOHO observations. EIT's images in He II provide sensitivity to solar structures an order of magnitude lower in temperature than those from the Soft X-ray Telescope (SXT), while maintaining overlap in the 0.6 to 3 MK range. If plans are realized, EIT and SXT operations will overlap for up to 18 months, allowing comparative analysis of their images. EIT's position at the L1 Lagrangian point ensures data continuity without interruption from Earth occultations, enabling access to a frequency domain in dynamical analyses previously inaccessible due to data gaps. EIT is a Ritchey-Chretien telescope with four multilayer-coated quadrants, each tuned to a specific wavelength band. The telescope uses a back-illuminated CCD with enhanced EUV quantum efficiency, cooled to -80°C. The CCD is automatically registered for the four passbands, and a filter wheel blocks long wavelength solar emission. The EIT's performance is supported by a dedicated electronics box (LEB), sharing a combined telemetry rate of 5.2 Kbps with LASCO. EIT's operations are integrated with LASCO, allowing for flexible and coordinated observations. The EIT's multilayer optics and filters are designed to optimize performance across different wavelength bands. The CCD quantum efficiency is calibrated to ensure accurate data collection, and flat-field calibration is used to correct spatial non-uniformities. The effective areas of each quadrant are determined by mirror reflectivities, filter transmissions, and the CCD's efficiency. EIT's operational modes include full-disk observations, selected areas mode, onboard desaturation, and coordinated observing programs with CDS and SUMER. It is operated from the Experimenters' Operations Facility (EOF) and uses planning tools to schedule scientific objectives. Routine operations include full-field images in all four EUV bandpasses, while real-time operations allow for flexibility in target selection. Data compression is used to reduce the data volume, with ADCT compression providing up to a 10:1 compression factor. EIT's versatility allows it to study a