Corrosion casts demonstrate the bisection of the human liver by the afferent blood supply. The lobar fissure is an important concept in surgery of the liver. Seventeen lobectomies and ten lateral segmental resections on the left elucidate major differences between these two resections. Lateral segmentectomy is quickly accomplished either by finger fracture with individual ligation or interlocking mattress sutures along the sagittal fossa. Important technical features for lobectomy are vascular isolation, maintenance of inferior vena cava flow, finger fracture of parenchyma, identification of hepatic ducts by intraluminal guides, T-tube drainage of common duct, operative cholangiography, and adequate external drainage. Regenerative hyperplasia progresses at an astonishingly rapid rate and angiography demonstrates compensatory dilation of the portal vein and the development of new arteries from the remaining hepatic. Serum albumin and glucose infusions are mandatory after lobectomy.