Erika,
Is this a general question to evaluate a purchase or do you have the book already and are curious about others thoughts?
Right now, I have read and worked through about half the book and have skimmed the rest prior to reading it through carefully. I would think that very beginning users would be somewhat baffled by the book as there are a number of assumptions of basic knowledge made through out. I suspect that such users would want another reference in hand at the same time they read the book or work through the excercises.
For those users with some knowledge, I think the book is a great resource. I know it has answered a number of questions I have had to date that no other resource has addressed. While none of these questions have been crucial, all of the answers have served to deepen my GDL knowledge and ability (spoken as someone with intermediate to early advanced abilities). I look forward to going through the next half, some of which appears to touch on subjects I have not worked through on my own to date.
I would be curious to hear other's thoughts.
Erich
AC 19 6006 & AC 20
Mac OS 10.11.5
15" Retina MacBook Pro 2.6
27" iMac Retina 5K