Diff between "join" and boolean "union"?

 From:  angeliclight
1689.3 In reply to 1689.2 
Michael, thanks much!

So, would you use join if you were modeling, say, a spaceship and you have the body, but want to put a lot of smallish details on the surface that look like small cubes, etc, glued on?

Do you only use boolean when you want one object out of two or more? How do you relate this to my above example, where you want lots of objects appearing to be "sitting on" or attached to the object underneath it, but not necessarily anything mathematically happening?

(Am I making sense with any of this stuff?)

Sorry if you had to repeat anything found elsewhere... :(

- A