Toughest Book or Section in L3?

Most of the reading seems easy/interesting. It seems the last half of Schweser Book 4 and the first half of Book 5 are the toughest readings. Anyone agree?

Derivatives and Fixed income are involved, like always the rest is just thick of terms and lists, blah blah.

toughest to read => economics, GIP toughest to apply=> equity management toughest to remember => derivatives formulas toughest time => not being able to out and play