Chapter 1 is completely trivial to anyone with mathematics training. It makes no difference to me if the author expands upon the section or not. It doesn't hurt my demographics of readership because we wouldn't read that section anyways. You know who would read it? The 'practitioner'. Someone that hasn't seen a matrix since high school or freshman year of college.

The interviews the authors give paint the picture this book is for the 'practitioner'. If Chapter 1 is meant for a brief review then don't advertise the book for a complete practitioner/beginner. Either make the book for the practitioner or not. If you do, then don't pretend to serve introductory math in it that the unfamiliarized reader will read and understand. They fail at their purpose there. So either make that chapter useful for the practitioner or leave it out and assume the mathematicians already know it. Maybe put it in an appendix and let us get to the meat quicker. It honestly does not take much time to define what a matrix is, give an example, define matrix multiplication, give examples etc. Same applies with basic definition and examples of derivatives. These are mindless mechanical procedures anyone can learn. It wouldn't take too much extra space to include some thoughtful examples. Maybe I should write an 'introductory group theory' textbook and start discussing geometric group theory 2 pages in if we want to get into not serving an intended audience's purpose.

I like what the author's are doing. I'm on their side, but I'm making suggestions that could serve a wider audience.

I didn't notice the appendices in the draft. This may help, but the version I reviewed has a brief review of Linear Algebra and Statistics in Chapter 1. The language is written in a way that assumes mathematical familiarity. Putting this level of 'sophistication' in a "practitioners" book early on may turn off a certain demographic of readers. I say 'sophistication' because it's relative to the reader-- to someone with a math degree this section isn't sophisticated (in fact they'd find it completely trivial) and can be skipped. To a software engineer that hasn't taken a Linear Algebra/Statistics class in 10+ years this may appear too much for them. You risk losing the readers entirely or having them skip those sections. Again, this review is not friendly for the beginner and the 'practitioner' title is misleading here.

In my opinion it wouldn't be too difficult or much effort to define what these mathematical objects are and show basic examples with basic computations to solidify the concepts. The notion of gradient descendent & derivates (or partial derivatives) isn't that difficult to understand and could be easily explained in a page or less.

For example when you discuss the Outer Product:

"This is known as the “tensor product” of two input vectors. We take each element of a column vector and multiply it by all of the elements in a row vector creating a new row in the resultant matrix."

It would be nice for the beginner to see an example of this and as stated it wouldn't take much space in the book to provide one. I think these sort of things would differentiate your book from others. If you made it more friendly more 'practitioners' would be willing to read/use it end-to-end.