Mirkat Always Reading

So I just had this (Gathering Blue) sent to my Kindle via my library's electronic collection, but now I'm not even sure I'll bother reading it.  It is nominally book number two of the quartet that began with Lois Lowry's The Giver, and I borrowed it thinking it would continue where the previous book left off.  But checking some reader reviews of it and the synopsis, I see that it appears to have NOTHING to do with The Giver, beyond arguably existing within the same world in some capacity.

I'm sorry, but this cheeses me off.  The Giver left in a cliffhangery kind of place, and then Lowry "continues" the series with a completely different story that Jonas isn't even in?  WHAT?!?!?!  And it looks as though the third book (Messenger) does feature Jonas, but many years later?  And the fourth book (Son) has a connection to the baby Gabe, from what I can gather.

Can someone who has read the entire series advise me as to whether I'd lose anything from just skipping over Gathering Blue?