Expository article on the Hilbert transform?

Wikipedia has an excellent article, probably more than you want to know:

https://en.wikipedia.org/wiki/Hilbert_transform

A quick search via Google yields the following results:

The Hilbert transform - Masters thesis by Mathias Johansson

The Hilbert Transform - by Frank R. Kschischang

Hilbert Transform and Applications - by Yi-Wen Liu