This chapter delineates the pivotal role of various imaging modalities in understanding anatomy, planning surgeries, and selecting conduits when necessary. It stresses the importance of tailored imaging protocols, collaboration with radiologists, and utilising intravenous contrastIntravenous contrast for optimal visualization. Emphasising the complementary nature of endoscopyEndoscopy, it highlights the significance of direct mucosal assessment and endoscopic interventionsEndoscopic interventions. Additionally, oesophageal function studiesOesophageal function studies are deemed crucial, especially in conditions like achalasiaAchalasia or after anti-reflux surgery complicationsComplications. Through a comprehensive approach integrating cross-sectional imaging, endoscopyEndoscopy, and functional studies, this chapter underscores the essential diagnostic foundations essential for successful oesophagogastric reconstructionOesophagogastric reconstruction.