There have been several books published recently that look at retirement planning and calculating the amount we need to accumulate for a secure retirement.  "The Number" by Lee Eisenberg has gotten a lot of attention.  The Wall Street Journal and several business magazines recently reviewed the book.  Mr Eisenberg details the challenges of retirement including inflation, health expenses and long life spans and just how complicated the "Number" really is.

BusinessWeek Online gives us their review.

USAToday.com gives a review.