I’ve probably read this essay slowly about a half-dozen times:
John Piper. “Are There Two Wills in God?” Pages 107–31 in Still Sovereign: Contemporary Perspectives on Election, Foreknowledge, and Grace. Edited by Thomas R. Schreiner and Bruce A. Ware. Grand Rapids: Baker, 2000.
It’s an incredibly helpful guide.
John Piper. Does God Desire All to Be Saved? Wheaton: Crossway, 2013.
It’s only 62 pages, and you could read it carefully in about three hours. And it’s available as a free PDF.
This little book significantly revises the essay. Piper wrote a new introduction, divided the essay up into four chapters, and then worked through it from beginning to end as if it were a draft. He ended up tweaking something in just about every sentence, added many new sentences and paragraphs, and updated old wordings and illustrations. The original essay is about 9,000 words; the book is almost 17,000 words.
I just slowly read the book, and I’m glad I did. Meditating on God’s two wills leads me to exult in his greatness.