Elemental Mastery

You must be Level 25 or higher to be able to pick up the Elemental book.

Qeynos Citizens: South Qeynos

You need to go to South Qeynos and head to the mage towers. Its the huge tower with the small pond around it, and a bridge in front. Go inside and walk into the red light to be transported to another floor of the tower. Head forward and down the stairs and you will find 3 NPCs. Two back against the wall, and one standing alone near the stairs. Near the one standing alone there are a few stacks of books.

To get the Elemental book, search the top of the stack of books pointed to by the white arrow in the picture:

Freeport Citizens: North Freeport

I have not found this book myself since I am not a Freeport Citizen. Here is the information I do have:

Go to the Academy of Arcane Science in North Freeport. Look for a blue book next to the NPC named Scribe Claudia Quarto.

Thanks to Kylin of Unrest for providing the information on the Freeport location, and Tilara of Kithicor for the image.