The topic of integrating F# and Microsoft Excel arises frequently, particularly in financial, insurance, statistical and data science work. There are several approaches to this, and in a recent discussion about F# in Finance, the topic of Excel DNA came up.  To quote: Excel-DNA is an independent project to integrate .NET into Excel. With Excel-DNA you can make native (.xll) add-ins for Excel using C#, Visual Basic.NET or F#, providing high-performance user-defined functions (UDFs), custom ribbon interfaces[...]