We present and discuss the design and implementation of \emph {modular explicits}, an extension of \OCaml first-class modules with \emph {module-dependent functions}, functions taking first-class modules as arguments. We show some difficulties with the present use of first-class modules and how modular explicits solve them in a simpler, more direct way. Modular explicits are fully compatible with, and can be presented as an extension of, first-class modules. Interestingly, both the formalization and the implementation reuse the mechanism designed to ensure principal types in the presence of semi-explicit first-class polymorphism and \OCaml polymorphic methods. Modular explicits are also meant to be the underlying language in which \emph {modular implicits}, \ie module arguments left implicit from their signatures, should be elaborated.