I am confused with this sentence:

**In the following decades, a great deal of effort was devoted to understanding the crystallography, phase transitions, and the optimization of this family of materials.**

Now, there are 2 ways of reading this, as I can see but I don't know which one is the right one. Help me, please.

First way:

understanding the crystallography of this family of materials, understanding the phase transitions of this family of materials, and understanding the optimization of this family of materials

2nd way:

[understanding the crystallography and phase transitions] and [the optimization of this family of materials].