The Microsoft Excel 12.0 Object Library is a COM (Component Object Model) library that provides a set of APIs for interacting with Microsoft Excel from other applications, such as Visual Studio, VBA (Visual Basic for Applications), or other programming environments.
Here are the steps to download and install the Microsoft Excel 12.0 Object Library: microsoft excel 12.0 object library download
If you have Office installed, follow these steps to reference the library in your project: The Microsoft Excel 12
Would you like help with converting your existing 12.0-dependent code to work with a newer Excel version? such as Visual Studio
If you have code referencing version 12.0: