Sequel to Land of the Silver Apples and Sea Of Trolls. Jack and Thorgil end up at Bard School, but not until the end of the book. Before that there is a bunch of rescuing and subdoing of scary creatures and such.
Sequel to Sea Of Trolls. Jack heads underground to rescue Lucy, who has been washed away by...well, it's just complicated. Good read. A map would have been nice, maybe.
Follows The House Of The Scorpion. I enjoyed it, and it sums everything up nicely without having to go into a third volume. Or a fourth (I'm looking at YOU, Paolini!)