It teaches Latin in a very cool way, where the entire book is written in Latin but it starts off with simple sentences anyone with a Romance language background can understand, before diving into deeper sentences, all while being illustrated so one can still follow the plot if they're stuck.
It contrasts with very dense Latin books that focus on grammar and spelling, which often bore students. LLPSI instead takes readers on an entertaining journey.
https://vivariumnovum.it/risorse-didattiche/propria-formazio...
That has a functioning link for the same content as the nina.coffee page tries to link to. There are several more French texts, as well as English, Italian, Spanish, and German.
There's an Icelandic text which isn't totally in Icelandic but, IIRC, is in the same vein as these. PDFs of it can also be found online pretty easily. I have not explored any languages beyond these as the two languages I'm interested in learning/practicing are Italian and Spanish, this content was sufficient for me.
Consider the perspective someone who does not know anything about this book previous to reading your comment. Searching Amazon for Hans H. Ørberg is not likely to make it clear which book (or books) you are actually recommending.
LLPSI Pars II, Roma Aeterna
These are the two main books. Each has companion books such as exercise books and teachers' guides. After these two, you should be able to read Caesar's Commentarii de Bello Gallico, but Ørberg also has other books.
As for whether the workbooks are worth it, I never used them, but then again I only read the main book for leisure, not in an academic setting or for serious study. If you're in the latter, then I'm sure the workbooks would help.
- Benjamin Kennedy's Revised Latin Primer
- Wheelock also remains a standard treatment.
I recommend the classical pronunciation by Ørberg himself.