The 50th Law is the fourth book by Greene—written collaboratively with rapper 50 Cent—and was published in 2009. The book mixes talk of strategy and fearlessness by supplementing anecdotes from 50 Cent's rise as both a young urban hustler and as an up-and-coming musician with lessons from various historical figures. Each of the 10 chapters in the book explains a factor of fearlessness and begins by telling how 50 learned this "Fearless Philosophy" in Southside Queens.