I played violin all through school and am now teaching beginning to intermediate lessons. I noticed in a duet book that it suggested different fingering that was not first position or third position? Did I miss something? I never remember playing anything in between first and third position...

2nd position (between first and third) is very helpful sometimes. Even in playing backup fiddle for folk singers I use it when they sing in B or Bb... and now and then F.
Hope this helps!
K.
http://www.folkfiddle.com