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.