Hello, I hope you don't mind another question from me (still trying my best to learn Ocaml). I have made a module signature (an .mli) file and module implementation (an .ml) file. They look sort of like this: (* TigerSymbol.mli file *) module type TIGERSYMBOL = sig ... end (* TigerSymbol.ml file *) module TigerSymbol : TIGERSYMBOL = struct ... end When I compile as follows: ocamlc -c TigerSymbol.mli ocamlc -c TigerSymbol.ml it complains on the second compile that: Unbound module type TIGERSYMBOL Any clues why this is so? Thanking you in advance, Christophe Poucet