Think is all about really going deep when reading the Bible and trying to understand, not just get through it. Piper talks a lot about how some people have the "gift" of thinking and some do not. I totally agree. I'm not really much of a thinker, and I need to do a better job trying to better understand the Bible. During the latter third of the book, Piper really focused on battling anti-intellectualism which says that we don't really need to understand everything, but just need to have faith. Admittedly, I'm in this camp, and struggle to move out of it. It seems that many people have pride in knowing exactly what the Bible means (Piper argues against this too), but we will never really know everything about God, heaven, theology, etc. until we get to heaven. Piper says that we need to lean more toward understanding instead of anti-intellectualism.

Some of my favorite quotes:
p. 35 - "If we are to live according to our nature as human beings in the image of God, and if we are to glorify God fully, we must engage our mind in knowing him truly and our hearts in loving him duly."
p. 63 - "We are an adulterous generation. We love man-centered error more than Christ-exalting truth, and our rational powers are taken captive to serve this adulterous love."
p. 80 - "Loving God with the mind means that our thinking is wholly engaged to do all it can to awaken and express the heartfelt fullness of treasuring God above all things." (probably the key quote in the whole book...he repeats if several times)
p. 90 - "To 'love God with all your mind' means engaging all your powers of thought to know God as fully as possible in order to treasure him for all he is worth."
p. 123 - "If we abandon thinking, we abandon the Bible, and if we abandon the Bible we abandon God."
p. 182 - "Humility is the great prerequisite for understanding the truth of God."
p. 184 - "Thinking that does not aim to display Christ and build up people is not worthy of God's approval."