If you don't know the book, by quality I mean it is packed with amazing charts, summaries and lines, and gives both sharp/attacking and positional alternatives for both black and white! Astonishing, but alas, many of our students are 1. d4 players!
(I do realize 1.e4 is inherently a lot "trappier" but many closed positions have plenty of gambits and tricks. In the most general sense, any threat a couple moves away that we miss was a trap, which is another reason Schiller/Watson is so amazing. Part of their power is their publisher,-- Cardoza is keeper of the keys of some of the top titles on ECO itself, and it shows in the 2020 printing of Schiller).