What is this book about?

A 49 lines poem on fiqh
Generally when scholars have a subject with 2 matters (2 words) they deal with it in 2 different ways or as if in one whole Definition
From the angle of it being a compunded words
- Al Qawaid : Foundation
- Al Fiqiyyah : The science of Fiqh It’s an attribution (nisbah) to Fiqh. Together they form the meaning of The Foundations of Fiqh.
From the angle of it being a singular title

hukmun kulli yataarrafu min hu hukmun ajuzziyyat al fiqiyyah mubasyaratan min bab
- Translation
  - Hukmun = hukum, a matter of which you can say true/yes/halal or false/no/haram to.
  - Kulli = kullu, comprehensive, all encompassing
  - Yutaarrafu = requires you to exert effort
  - (min hu) **Hukmun ajuzziyyat **= there’s an outcome of it
  - **al fiqiyyah ****= pertaining the issues of Fiqh
  - mubasyaratan = you understand them right away Basically these principles can be applied in so many chapters or areas of Fiqh.

What is the difference between this book and usool al fiqh?