I think I am starting to confuse myself the more I think about this. Lets say we have two Transactions, T1 & T2.  If we execute T1 then T2 once T1 is finished, this would be serializable and serial.  Now my confusion is what if we reverse the order, T2 gets executed first then T1.  It's still ends up being serial but does the order of transaction matter?

I'm thinking the order of transactions does not matter, because these transactions are not related or dependent on each other.  This is what I understood from the book.