This an exceptional supplement. The writing is excellent and the interior artwork perfectly fits the Planescape tone. The chapters are often written as if advice given to new planewalkers, and the interior art includes helpful (and sometimes humorous) diagrams for the planar concepts. The content is an update and consolidation of the original Planescape campaign setting boxed set. In many respects it does a better job (in my view) of explaining some of the core planar concepts than the boxed set does, e.g., the portals, gates, conduits, vortices, and paths chapter is especially clear.
The scan is good quality. A few minor points about the PDF: The book uses a pale gold for headers and epigraphs which seems to fade or become blurred in smaller and lighter weight fonts on some pages, e.g., the sub-headers are a lighter weight than the main-headers on pages 42-53 and as a result are a little blurry. The OCR is excellent, as well as the table of contents structure, which makes the PDF quickly and easily navigable. It would be nice to include OCR also for the titles of the chapters, e.g., a search for "Traveling the Multiverse" should take me to page 34 where this chapter begins. Instead it takes me to page 68 where the "Traveling the Multiverse" chapter is mentioned in the text itself.
In sum, I highly recommend this book; It should be read alongside the boxed set by both players and DMs.
(2e mechanics are able to be converted to 5e by using Wizards' conversion document available for your home games here: http://media.wizards.com/2015/downloads/dnd/D-
[5 of 5 Stars!]