I will confess that for quite a while, when I first started working with databases, I did not really understand that joins weren't just another part of the where clause.
But they're not even remotely such a thing and frankly, I find it disturbing that someone billed as an "editor specializing in database and programming titles" might lack that fundamental knowledge about what relational databases are all about. This ignores, of course, that there are no truly relational products out there, including Oracle. Rather, they're all SQL databases, and SQL isn't truly relational.
I think it behooves someone editing books about databases to understand that difference. It's pretty sad that I didn't know this for so long, but anyone involved in the creation of database books should have a pretty solid understanding of relational theory.