This chapter discusses surgery of the frontal sinus that are generally paired, asymmetric structures found within the squamosal portion of the frontal bones. The frontal recess is a potential space that is pneumatized by various cells, and, thus, the use of the term nasofrontal duct is discouraged. The agger nasi area is found just anterior and superior to the insertion of the middle turbinate into the lateral nasal wall. A variety of frontal cells can pneumatize anteriorly into the frontal recess in conjunction with the agger nasi cell. Frontal bullar and suprabullar cells reside superior to the ethmoidal bulla. Intersinus septal cell pneumatizes the frontal intersinus septum and may result in substantial narrowing of the recess medially. The pattern of mucous transport in the frontal sinus is superiorly along the intersinus septum, laterally along the roof and then medially along the floor of the sinus.