They are very similar books. I bought both and read both of them. Secrets 2 was almost the same information as Crush 3. Crush had a litte more information about optho and derm stuff that was not included in Secrets 2. There is no USMLE secrets for Step 3 book. I would just read one of them before the test if I were you. I took Step 2 about a year before Step 3 and it was agonizing reading Crush 3, because it was like reading the same book again.