Part of my site is structured as a large book. I often want to display blocks in certain parts of the book. There seems to be designed way of doing this. For second tier book nodes (can I call them book chapters?), I use the work around of reaction triggered based on menu (as I have enabled the book title and each chapter name in my main menus).

However, this is impractical for 3rd / 4th book tiers, and I wonder if this could be incorporated in context or one of its sub modules sometime?