This is an excellent book and necessary if you're interested in a career as a back-of-the-book indexer. There are issues though on which version you should read.
I have both the hardcover book and the Kindle version. I mostly read the Kindle version. There is also the Kindle version you can read on your laptop. I stopped reading the laptop version pretty early on. When reading about creating indexes, it is important that the indentations are correct. Indexes are made up of headings, subheadings (and sometimes sub-subheadings), and locators. Publishers have standards on the spacing of indentations. Things like en- and em-dashes are important.
On the laptop version of this book, the formatting of the index examples do not work. Several times I had to grab the IRL-book to see what the author was talking about. The Kindle was closer to the book in that regard. Therefore, I have to recommend if you want to read this book to only read it in the actual-book form.
Unfortunately, I left the actual book at home as I'm traveling now. The Kindle version does have a few instances of messed up indentations, but by the time I got to them, I knew what she was trying to show.
This was an expensive book for Kindle, but an important addition to my library. It cost me $24.75 back in 2011, bringing 2020's book expenses up to: $461.86.
For the Dewey Decimal challenge, this one is 025.3.