Question

Hello,
I read The Spirit of the Law at the time, and now I’ve finished the first two roots in Maimonides from It Shall Send Forth Its Roots. As far as I remember, I think these are really the exact same things — both in the conclusions and in the presentation of the material, etc.
My question: on the cover of It Shall Send Forth Its Roots, additional authors are listed. What did they add? Was it only the language editing? Or maybe they added content later on in the roots? Or perhaps I missed something…