From the README:

This is a raw OCR engine. It has NO PAGE LAYOUT ANALYSIS, NO OUTPUT FORMATTING, and NO UI. It can only process an image of a single column and create text from it. It can detect fixed pitch vs proportional text.

Having said that, in 1995, this engine was in the top 3 in terms of character accuracy ..

Another current limitation is that it only recognizes English and its character set is only US-ASCII. Training code IS included in the open source release however, and

will be included in a future release.