If you're a working programmer looking for a bit more depth on text searching, check out Taming Text by Ingersoll. It was written by some real pros, and it's very practical. It goes over everything from the first naive approaches to what drives many engines like Lucene today.

https://www.amazon.com/Taming-Text-Find-Organize-Manipulate/...

Taming text http://www.amazon.com/Taming-Text-Find-Organize-Manipulate/d... Natural Language Processing with Python http://www.nltk.org/book/