Hi Mauricio,
We are looking forward to your book - it is greatly needed. While the existing jBPM documentation provides a good overview, much more technical detail is needed. We are particularly interested in Human Tasks and application architecture suggestions. I would not use the pages to explain rules and Fusion since they are explained in other places. I would also like to see examples that are simple and demonstrate just the feature they are about, instead of large complicated examples that require one to understand everything in previous chapters.
Regards