In this report, we first describe the history of transsphenoidal surgery. We further elaborate on three fundamental surgical anatomy principles of transsphenoidal surgery for pituitary adenomas. First, the pituitary gland and, therefore, pituitary adenomas are extra-arachnoid structures, therefore the operation should be executed without penetration into the subarachnoid space. Second, the pituitary gland and, therefore, pituitary adenomas are midline structures, thus, veering off midline can result in potentially serious complications. Third, pituitary adenomas commence inside the pituitary gland, which distends around them as they grow. Thus, pituitary macroadenomas are surrounded on their surface by a layer of attenuated residual normal anterior pituitary. The operative technique for pituitary micro- and macroadenomas is described in detail. Finally, we discuss the likely future treatment methods for pituitary adenomas.