Clayton M Chistensen, the HBS innovation guru, was diagnosed with follicular lymphomo, and an ischemic stroke. He fought the illness successfully and released a new book titled How Will You Measure Your Life ? which has a genesis in a lecture he delivered to graduating class of 2010. The book is co-authored by James Allworth and Karen Dillon. The sources of happiness are the relationships with the family and friends, the work we do and things you can do in life that can deny us these sources.