There are different ways to create context sensitive help,
because it takes both the help author and developer. Dividing that
labor can be done in different ways. Essentially, the process
involves the developer creating help links (map numbers) generated
from F1 or help buttons in the application. If this is already
done, you can read those with a tool like Bug Hunter (from
RoboHelp) or Help Workshop (from Microsoft).
Help then has two files - an .hh file, which connects the map
# with an ID, and an .ali file, which connects the ID to your
topic. No, you cannot connect to a book but if the book is
configured to display a topic you can connet to that topic.
RoboHelp will create these two files for you. Look in your
RoboHelp Help to get started, but also talk to your developers to
see how nuch is done already on their end.