Always a book.
Of course my phone, wallet, and keys.
Also a spare dose of E in case I'm out longer than I expect, a snack (now a container of honey roast peanuts), a tube of hand moisturizer, a comb, pen, pencil, pad of paper, spare sanitary pad. There are also a few giftcards that at various places if I find occasion to use them.
And deep in the hidden compartment, my carry letter. Probably a bit worn by now.