Harlow Giles Unger's 2002 biography, Lafayette, is worth looking into. Librarians give it high marks. Reviewers style it "dramatic." Unger attempts to reveal Lafayette's live as he lived it through two very different sorts of revolutions. Adrienne Lafayette, his wife, is an important part of Unger's biographical account.

Another excellent work, though intended mostly for a scholarly readership, is Lloyd Kramer's Lafayette in Two Worlds. It deals equally with Lafayette's considerable career in France as well as his involvement in the American Revolution and his triumphant tour of the nation decades later. It treats Lafayette in his historical context, as part of two revolutionary movements as well as the eighteenth-century Enlightenment and the emergence of nineteenth-century liberalism. I second readerofbooks's excellent suggestion to consult the bibliography, and, if applicable, footnotes to find other books. 

This is a good request. There are many books and works on Lafayette (September 6, 1757 – May 20, 1834). So, you will have to be selective. I would suggest that you read broadly to get a few different perspectives. Moreover, you might want to get the latest book by a responsible scholar, because this will give you the most up to date bibliography for further research. In light of these two suggestions, let me give you a list of works. 

For a recent book, see:
David Clary. Adopted Son: Washington, Lafayette, and the Friendship that Saved the Revolution.

For a solid work:
Saba Holbrook. Lafayette, Man in the Middle.

For a military perspective:
Marc Leepson. Lafaytte: Lessons in Leadership from the Idealist General. 

For a selection of sources:
Marie Joseph Paul Yves Roch Gilbert Du Motier Lafayette. Memoirs, Correspondence and Manuscripts of General Lafayette.

These books should get you started and make sure to look at the bibliographies for more information.