What's the difference between ALL_TABLES and TABLES?

The docs are unenlightening: * [ALL_TABLES]: > Provides summary information about tables in a Vertica database. * [TABLES]: > Provides information about all tables in the database. The reason I'm asking is that users are confused about why they can see some tables in one but not the other. It's related to permissions, but it's not clear exactly how. For example, a user is telling me they have access to query a table. However, that table doesn't show up in TABLES and its columns don't show up in COLUMNS, but the table _does_ show up in ALL_TABLES. So, this leads to the following questions: 1. What's the difference between ALL_TABLES and TABLES? 2. How can users see a list of all the tables (and columns!) they have access to query?