I was recommended this book when writing my undergraduate dissertation a year and a half ago, and I found it a very interesting, indepth, and well researched. Rather than focusing on his professional life, Lacey, has gone right back to his childhood and the history of his parents, which provides a good background context to the adult life of H.L.A. Hart. Also, when writing about his work, specifically "The Concept of Law" Lacey has covered all aspects including other forms of interpretation and why he was used other philosophers e.g. Wittgenstein and "Philosophical Investigations." This book helped me not only understand more clearly Hart's work but also how future interpretations and wrtings could be achieved. It is also both funny and sad in places, and does reviel areas of Hart's life that would have been rather difficult if made public during his career.
A good read and excellent source of reference for anyone interested in law or philosophy.