A few years ago I bought a copy of the daily devotional book Resist the Powers with Jacques Ellul by Charles Ringma. For each day there is a short Bible passage and a reflection containing a quote from Jacques Ellul.
Every few days I read a page. Of anything I have read over the past few years I think this book has had the biggest influence. It really does present a radical view of what it means to follow Jesus and what the nature of the Kingdom of God is. Ellul was certainly a creative and radical thinker.
The book was my first introduction to Charles Ringma and I was delighted when a few years ago I got to meet him in person and be part of a theology book reading group that he leads.