The New Personality Self-Portrait25, or NPSP25 is the work of psychiatrist John M. Oldham, M.D., in longtime collaboration with mental health journalist and author Lois B. Morris, and more recently, psychologist Alok Madan, PhD. 

The NPSP25 is an updated, internet-only version of a book first published in a 1990 by Oldham and Morris, called The Personality Self-Portrait: Why You Think, Work, Love, and Act the Way You Do, with the the second edition remaining in print since 1995.

Find more at the NPSP25 website.