Context: I'm a leather pattern maker with 30 years of apparel production experience.
First, this book amounts to an updated and revised edition of Ms.Sterlacci's other leather book, Leather Apparel Design. Meaning, if you have that, you may not need this one. Then again, the book is so inexpensive it could be well worth buying anyway.
Pluses: I would consider this to be a thoughtful, comprehensive but beginning introduction to a career in leather design and manufacturing. The text includes an intro to leather garment history (neat photographs), a survey of leather tanning processes (somewhat boring if you're not given to such things but well written and palatable to non-technical readers), an explanation of weights and finishes as well as some advice on cutting, seam finishing and sample sewing projects (a coat, pants and shirt).
Minuses: I don't think the content dedicated to planning, costing and what not is particularly useful because it is beyond the scope of the book to do that well. My point being, it didn't need to be here because you should get other books on just those topics (I wrote one so consider the source). Still, it's not bad for someone who has never looked at these types of constraints that are critical in apparel design but you do need more. Much more.
Being that I read so many reviews, I often find conflict between buyer's expectations versus (what I think) is reasonable. To that end, this book does not claim to be a leather sewing book. It is not a leather pattern making book. So, if that's what you're looking for, that isn't here. I still think you need it if you're serious about the topic.
I do have differences of opinion with the author but these are minimal and amount to varying experience and perspectives. She was a designer and instructor and I've worked in leather pattern making and production. To outsiders these seem to be one and the same but they are very different. In spite of my differences of opinion, I reiterate that this book is an excellent value and consider it well worth purchasing.
I disagree with her advice on seam allowances (should be 3/8" & 1/4", not 1/2" & 1/4").
I think that cutting with a blade around a pattern piece is one of the best ways I know of to go broke slowly. Only, by the time you've figured out that slivers of your pattern have been cut away and your patterns no longer fit and sew together, you would have gone broke already.
I don't agree with her advice on pressing. I get lousy results using paper. A teflon shoe on an iron is much much better. I also disagree on steaming the leather. I do however, completely agree that tricot fusible is wonderful stuff.
I don't like glue, it's very toxic. Sure, you won't be handling it much but the people who sew for you will. Where ever they live, it still causes cancer. I think there are better ways to eliminate the need of glue and it makes for a better product.
Summary: At $26, I think this book is an outstanding value and a must buy. I've detailed more of the content on my site as well as comprehensive articles as to why I disagree in my opinions above but this won't publish if I paste those links here. No matter. My site is easily found if you're sufficiently motivated.
Off topic: if you buy this book, enjoy it and find it useful, please consider leaving a review. Authors depend on them. Of the 8 reviews published as I write this, 7 of them are fake. It is tragic that a book as integral (there is no other book like it) as this one, has so little support from the buying public.