Are legato and slur one and the same? If the two are different, how do I tell which the piece is using? I know the gist of them (as opposed to staccato) but I need to know the specifics. They are notated the same (I believe). I am speaking of a wind instrument. Does this make a difference in the way they are played?
Legato is a technique, whereas a slur is a marking. As for what a slur denotes, Wikipedia does a pretty good job of handling the distinction between that and legato (see Slur and Legato). The most relevant quote from the legato article:
The slur article notes that with some wind instruments, you should play each slurred note without using the tongue to rearticulate the note.