Professor David's Les Grands Systems de Droit Contemporains is acknowledged as a classic in the literature on comparative law. It provides a discursive account of contemporary families of law, analysing their history, development and present day structure.
Although the book is obsolete, it's classics of the subject. The author's language refrains from scholastic comments and terminology making the book an easy and informative reading. I re-read it a few times (different editions in different languages), and I always find smth. new for my scholarship.