This won't teach you how to sew, but it may provide a foundation for pattern manipulation and drafting.
Using this book I was able to draft using software (Valentina is a great free option though can be daunting to learn as it's rather technical) to create skirt, pants and bodice blocks. I've used the skirt and bodice blocks to make full garments or correct commercial patterns. Eg correcting the bust dart(s).
Following some of the adaptions, I've altered commercial patterns, such as splitting the front to have a yoke, rotate the dart to the shoulder and add fullness to gather into the yoke instead of a dart.
The book does not include construction methods or instructions, for that I use my stash of commercial patterns, other sewing books or even checking Youtube videos or blogs from other makers for similar designs to see how they do things. This book provides a very specific part of creation a pattern, not how to make the garment.
I've been wanting to understand patterns and garment fitting better after falling into the historical costuming world on YouTube and having dabbled in sewing for most of my adult life but struggling to actually end up with something I will wear beyond a circle skirt.
Pairing this with the amazing tutorials from Closet Historian on YouTube has developed my understanding of clothing construction by leaps and bounds compared to what years of just using commercial patterns ever did.