Lucene.Net is a port of the Lucene search engine library, written in C# and targeted at .NET runtime users. The Lucene search library is based on an inverted index. Lucene.Net has three primary goals:

1. Maintain the existing line-by-line port from Java to C#, fully automating and commoditizing the process such that the project can easily synchronize with the Java Lucene release schedule;
2. Maintaining the high-performance requirements expected of a first class C# search engine library;
3. Maximize usability and power when used within the .NET runtime. To that end, it will present a highly idiomatic, carefully tailored API that takes advantage of many of the special features of the .NET runtime.

Learn more on the Lucene.Net project page.