I have used Telerik JustDecompile on a number of occasions, for things such as tracking down bugs in third-party libraries, recovering essential project source code that has been lost, checking the strength of assembly obfuscation, and for learning purposes. It is a tool that I highly recommend, as over the years it has proven its worth many times.
The decompilation engine is open source and you can obtain the source code from https://github.com/telerik/justdecompileengine, so you are free to contribute to the project and write your own extensions for it. You can download Windows Installer from the Telerik website, at https://www.telerik.com/products/decompiler.aspx. All source code is fully navigable. The decompiler is available as a standalone application or as a Visual Studio extension. You create VB.NET or C# projects from assemblies that you decompile, and you extract and save resources from the decompiled assemblies.
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