I ordered a book online for one of my classes on Thursday. It just shipped around midnight. My mother in law needed me to run some errands with her. We went to about six or several places, I misplaced my credit card while running the errands with her. I had to cancel credit card and had my money transferred over into a new banking account. I did notify the seller that I had changed credit cards and to charge the card credit ending in the last for digits instead.

The odds that a seller would divert a shipment (only possible with UPS and Fedex, not the PO) over a book are extremely low.
BUT you don't know if the book was actually out of the building or if they just bought the postage label. I suspect that they won't stop the process even if hasn't really left let.
If you have a tracking number, just keep tabs on it. PO tracking isn't really tracking, however, it just has to confirm delivery, and anything in between you are just lucky to get.

A purchase is not shipped until your credit card is charged and the charge approved. So if it shipped the old number was already charged and that charge will be transferred to the new account.

ScottGem, my experience and what I have heard is that when you report a lost card, recent charges are cancelled. Not sure how far back 'recent' is, but surely the same day, as this was.

Only charges made after the report are cancelled. The cardholder will have the opportunity to cancel any charges transferred over that they feel were fraudulent.

When the merchant presents the charge, the account is charged and the merchant credited.

Countless people over the years I spent on the eBay boards said that their charges made just before they reported the card lost were cancelled, as much as a few days, apparently on the grounds that they didn't know when the card was lost, and probably because there was no human interaction to verify which recent charges were verified as the cardholder's.

I agree with Scott from everything I have ever seen they tend to have your card charged and processed pretty much as soon as the order is in.

In these days of electronic processing, this is all immediate. If anyone claims a charge was cancelled, then it wasn't processed completely before the account was locked.

I should have said reversed.
No one here has ever done a chargeback? I have - a month after the charge was processed.

Sure, reversals happen all the time. But, as I said, charges are immediate. When a merchant processes a charge these days, the account is debited and the merchant account credited immediately. Some merchants may not have their own accounts and process payments through a 3rd party. In such a case, they may batch their transactions through the 3rd party. But I don't know of a merchant that will ship until they receive confirmation of payment.

BUT a merchant can mark as shipped at midnight and that doesn't mean it shipped.
They can even buy postage and you see a tracking or DC number, but it may not have gone out.
I have a ton of experience with all this.

True, but they won't even do that without getting credit approval.