There is an enormous number of books about Luther, and tens of thousands of articles appearing in both popular and scholarly journals. The following is intended to guide those who might want to explore Luther and his world more deeply.
Every serious student of Luther should read Luther's own works. Most are easily available in English translation. The standard scholarly edition in English is the 55-volume Luther's Works, known commonly as the “American Edition” (Concordia/Fortress, 1955–1986). This is the most complete collection of Luther's writings available in English, and is commonly held by larger libraries. It is also available in a CD-ROM edition, which has the distinct advantage of being searchable by computer. John Dillenberger, Martin Luther: Selections from his Writings(Anchor Books, 1961) and Timothy Lull, Martin Luther's Basic Theological Writings(Augsburg, 2005) are both good onevolume compilations. Many of Luther's key works are also available online through the Project Wittenberg website (www.projectwittenberg.org).
There are literally thousands of biographies of Luther, and not all are worth reading. Martin Brecht's three-volume Martin Luther(Fortress Press, 1985–1993) is widely considered to be the scholarly standard. James Kittelson, Martin Luther the Reformer(Augsburg, 1986) and Derek Wilson, Out of the Storm(St. Martin's, 2007) are both readable single-volume treatments. Once considered a standard, Roland Bainton, Here I Stand(Abingdon, 1950) now seems a bit dated, but can still be valuable. Bernhard Lohse, Martin Luther: An Introduction to His Life and Work(Fortress, 1986) is not a biography in the traditional sense, but rather an outline and summary of the key topics and issues in Luther's career. Heiko Oberman, Luther: The Man Between God and the Devil(Yale, 1989) is powerful, but can be difficult. Many shorter biographies only cover portions of Luther's life. Some of the more helpful of these are Heinrich Boehmer, Martin Luther: His Road to Reformation(Meridian, 1957), Heinrich Bornkamm, Luther in Mid-Careeer, 1521–1530(Fortress, 1983) and H. G. Haile, Luther: An Experiment in Biography(Princeton, 1983).
To get a sense of the broader picture of the reformation and Luther's place in the larger movement, Carter Lindberg, The European Reformations(Blackwell, 1986) and Euan Cameron, The European Reformation(Clarendon, 1991) are very helpful.