The chapter offers an overview of certain issues that have been extensively discussed in the literature on the syntax of adjectival and adverbial modification. It presents discussion on the lexical status of modifiers, distributional and semantic classifications of adjectives and adverbs. The chapter also discusses a number of proposals concerning the licensing of modifiers and one influential proposal that adjectives and adverbs are specifiers of designated functional projections and the problems this faces. An influential view holds that both adverbs and adjectives are specifiers of designated functional projections in the verbal and nominal extended projections, respectively. The antisymmetry-based approaches to adverbial and adjectival modification opened up a very fruitful way to deal with this issue that led to a number of fine-grained descriptions of the behavior of adjectives and adverbs across languages as well as significant cross-linguistic comparisons.