VLOOKUP is all very well when the data is arranged in the right way for the function - with the thing you're looking for to the left of the thing you want to return, but what happens if you want to do the reverse of VLOOKUP ?

Well, fortunately help is at hand with INDEX + MATCH.

MATCH returns the position of a value in a range INDEX returns the value of a cell that is offset from another.

Combined, you can use INDEX + MATCH to simulate VLOOKUP, and to do the reverse lookup as well as the VLOOKUP:

Index Match Spreadsheet

Training Video on VLOOKUP INDEX MATCH