“Anatomical” resection of the liver refers to the removal of a functional segment of hepatic parenchyma with defined boundaries dictated by the main division of the Glissonian branches. This technique has the advantage of completely removing the tumor-bearing portal territory to achieve a radical resection. Simultaneously an anatomical resection maximizes the amount of remnant liver, which is of utmost importance in patients with underlying liver disease or with altered liver function due to systemic treatments. Left lateral sectionectomy (LLS) refers to the en bloc resection of the lateral part of the left liver corresponding to the Couinaud segments II–III. A left lateral sectionectomy is an important milestone in the learning curve of open and minimally invasive hepatic surgeons. General principles regarding surgical indications, preoperative planning, and the key operative steps of these procedures are the object of this chapter.