Quite a dodgy source if you're looking for info on Medieval Catholicism, as opp. to Renaissance Protestant propaganda, no?
Tell me more!

If you really want to know ... (I love a chance to quote a bit, and it is on-topic).
Foxe's account is pretty biased pretty much all the way through. He's very clear that Catholics are bad, and Protestants are persecuted. He also likes to give pretty anecdotes about the noble deaths of Protestant martyrs (eg. those who died during Mary I of England's reign). Quotations from the same link Gamma Ray put in above; they're from Chapter 16.
He's famous for the account of the deaths of Latimer and Ridley, leading Protestants during Mary's reign, who were burnt at the stake in Oxford. (There's a memorial to them a little way down the road from my house). The story goes that, as they were led to the flames, Latimer said to his companion,
'Be of good cheer Mr Ridley; and play the man. We shall this day, by God's grace, light up such a candle in England, as I trust, will never be put out'. From a propaganda point of view, this is clever: Foxe was a good Protestant and didn't like the veneration of the old Catholic saints, but he made his martyrs sound like new, Protestant saints.
He also tells how Archbishop Cranmer died. Cranmer was the translator of the Anglican Book of Common Prayer and the English Lord's Prayer. He was also Henry VIII's bishop, who married Henry to Anne Boleyn and therefore, I suppose, he was one of the people who orchestrated the end of English Catholicism. He was an old man when he was persecuted by Mary I's government for refusing to give up his Protestant faith. At first, he was tortured and he signed the confession that was required of him, in which he denied his faith. He was, despite this, sentenced to be burnt to death. He was ashamed, and - according to Foxe - took back his denial of his faith. He said that, in signing the denial,
'my hand hath offended, writing contrary to my heart, therefore my hand shall first be punished; for when I come to the fire it shall first be burned'. He was put on the pyre in the same place where Latimer and Ridley had been burnt, and he held his right hand into the fire until in burnt to a cinder, before dying.
...
Or at least, this is Foxe's version. The justification for thinking about Foxe in the context of the medieval Catholic Church is, I guess, that his version of events influenced historians for a long time. Even in the last century (20th), it wasn't uncommon for historians to get their view of the abuses of medieval Catholicism from the early Protestant sources, like this one. For example, Foxe gives an account of the Wycliffite movement of the late-fourteenth and fifteenth centuries. The Wycliffites desired an English (not Latin) Bible, and increasingly challenged the power of the clergy and what they saw as the corruption of the Church. Some of their followers also challenged the doctrine of the Real Presence, claiming that it was absurd to think God could be in bread and wine. Foxe's account makes Wycliffe, the leader, sound like a man of great insight who just lived too early, and still you see historians' accounts that take Foxe's view and think that anti-Wycliffites were all corrupt or reactionary (which they really weren't!)
Anyway ... I guess this is more to do with the historiography and the last gasp of Medieval Catholicism, so I don't know how useful it will be, NMHS. Sorry if it's a total digression - I love this stuff you see!
Liz.