Where can I find the Microsoft .NET Framework Development Guide?

It's called "Design Guidelines for Developing Class Libraries" and can be found here in the MSDN

As you figured out yourself, the article you were originally looking for is called Design Guidelines for Developing Class Libraries on the MSDN.

Note that it also exists a great complete book on the very same topic, named Framework Design Guidelines. Actually, the MSDN page encourages you to have a look at this book if you want to go deeper:

For more information on design guidelines, see the "Framework Design Guidelines: Conventions, Idioms, and Patterns for Reusable .NET Libraries" book by Krzysztof Cwalina and Brad Abrams, published by Addison-Wesley, 2005.

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