<<I need to create a new Image dataset. I want to retrieve the records in reverse date order (LIFO). I was going to do a backwards chain read. Someone told me that a reverse chain read was not efficient.>> "Someone" is confused or misinformed. IMAGE detail dataset chains are doubly-linked lists, so it is just as efficient to go backwards as to go forwards. If the chain in use is the primary path of the set and the set has been recently reloaded/repacked, there will be a slight advantage to a forward-chain read courtesy of the disk subsystem's read-ahead provisions. For most real-world situations, this advantage is minimal to non-existent, and reverse chain traversals will not show any differences from forward traversals. Steve