A curious book. It feels the need to offer instructions in a comic book format, so a make and female beginner are asking an established manga artist how to achieve pen effects, etc. It increases the page count but isn't the most efficient way to learn - but no doubt more user friendly for younger readers.
The art style of the comic is pretty basic (or terrible, depending on your aesthetic). The nicest thing I can say about it is like gag manga maybe the pictures aren't so important, but that doesn't necessarily excuse publishing weak art. Thankfully the technical examples (the actual lessons) are very well drawn.
The book might not be useful to most of today's audience given a lot of the tech has been greatly improved e.g. digital software now has "screen tones" to apply shading and effects to (digital) art, for instance, while this books covers logistics if how to buy physical screentone sheets and cut them out/stick them down over art drawn on paper.
The book however does have good technique (drawing from the shoulder where needed, etc) and for anyone using real life paper and ink tools there's some useful tips in here.
I personally find it a novelty/antique/time capsule showing the difficulty and tricks/techniques manga used to require to draw, as well.