This talk will introduce F#, an ML-style programming language with a core language akin to that of OCaml. The aim of the F# project is to make ML-style functional programming fit as well as possible with the .NET Common Language Infrastructure (CLI). For example, components written in other .NET languages are extremely easy to use from F#, and likewise F# components can be used directly from languages such as C#. Core OCaml is taken only as a starting point, and this talk will highlight how platform-centric thinking leads to the reconsideration of many of the design decisions that led to OCaml and Standard ML, particularly with respect to modules, value recursion, object-orientation, cross-language interoperability, controlling effects and library design. F# is available for download from http://research.microsoft.com/projects/fsharp.