It might be worth mentioning that the titles of those two Popper books are the reason why Imre Lakatos's book recommended in the OP is called "Proofs and refuta

It might be worth mentioning that the titles of those two Popper books are the reason why Imre Lakatos's book recommended in the OP is called "Proofs and refutations: the logic of mathematical discovery". (I don't think knowing this makes any particular difference to how one reads any of the books involved; it's just amusing.)