Dallas Willard wrote some of the most important Christian books of the late 20th and early 21st centuries. Among his most significant works were The Spirit of the Disciplines, The Divine Conspiracy, and The Renovation of the Heart. I discovered him in seminary when I checked out his lectures on The Divine Conspiracy. Had I discovered him earlier, I believe I would have matured sooner as a Christian. Here some tributes not only to his work but to the man himself:
Mark Roberts, Parts 1 and 2.
From Scott McKnight at Jesus Creed.
Christine A. Scheller, John Ortberg, Richard Foster, from Christianity Today.
Kevin Watson, from his Vital Piety blog.
Scott Smith, from the Evangelical Philosophical Society blog.
J.P. Moreland, from his blog. Also from J.P. Moreland's blog, this short tribute from Juliet Setian.
Wesley Hill at First Things.