Designed by Patrick Ng it's an alternative form of time management and he originally designed it for the Midori Traveler's Notebook. This time last year I used my large Midori notebook as inspiration for a pocket version (with the added advantage that it would take moleskine cahiers/ field notes as well as Midori and Paperchase passport sized notebooks).
I've been using it all year - can't imagine using anything else and it's holding up pretty well. (I'm also still using the larger version as a sketchbook). The Midori passport sized accessories fit so I've added a pen holder and clear pockets. It takes up to 4 notebooks and last year one of them was a diary. The diary covers all areas of work - but then I also have space for a separate notebook for each area which is perfect.