Hi Laubernder, thanks for your response.
If it's possible I don't want to open 230 files and use the find and change panel to perform the change in all the opened documents.
This the first book I have, there is another one with 180 files, so i wonder if it possible to code a script that find and change an expression in the files (without open it) of an existing book file. I assume that if it is possible find/change a single expression, i can loop an array populate with expressions to perform the find/change.
It's not even possible to open 230 documents: InDesign lets you open about 115 documents. One way to go about it is to create a simple script to do the replacement in one document, then use that script in a batch-processor like https://creativepro.com/files/kahrel/indesign/batch_convert.html
P.