I'm relatively new to programming and used both Caminstructor and eMastercam books within the last couple months. I found that the Caminstructor books were a little easier to follow but they both covered the same concepts. I used my bosses old Caminstructor books waiting for the eMastercam books to arrive and I think I might've gotten lost had I started with eMastercam. That being said, I refer to the eMastercam books quite a bit more often now that I have more of an understanding of what I'm doing.