What is Logging? Logging is the act of keeping a log. The log file is a file where all events or error of application is written. Reference: - https://en.wikipedia.org/wiki/Log_file Logging is an important part of application; how much we try to build application error free but some errors are there which occurs conditionally to log this kind of error we need use some logging libraries, for example, some errors may occur due some database server is down or some application functionally is not working properly how we are going to know if we don’t have proper logging setup we would not able to know what functionally is not working at client end. There is a well-known phrase from developers “ it works on my machine ”. To know what is going wrong in your application logging is important. Link to Article:- https://www.codeproject.com/Articles/1278018/Best-Logging-libraries-for-ASP-NET-MVC