Paul Tripp's book, A Quest for More: Living for Something Bigger Than You (also available as a study/discussion guide) is well worth the read--especially for the insights about the kingdom of self vs. the kingdom of God. You can read chapter 1 online for free.
Justin Buzzard has done us a great service by taken Tripp's summary statement--and concluding question--from each chapter and posted them here. Working through this can be a great means of leading to healthy heart examination and Christ exaltation.
