Here are some other summaries by other legal theorists which you may find useful!
THE CONCEPT OF LAW PREFACE
HLA HART
OLIVER WENDELL HOLMES
THE GROWTH OF SCIENCE IN SOCIETY
MICHAEL POLANYI
OLIVER WENDELL HOLMES
HARD CASES (EXCERPT)
RONALD DWORKIN
THE THEORY OF SOVEREIGNTY RESTATED
W.J. REES
Straight from the Hart 