I must disagree with the first reviewer of this book. I found this "Introducing..." installment to be unclear and unhelpful, unlike most in the series. The author hurls terminology at you with little, and sometimes no, explanation. Each page seems to introduce a new concept without building on the previous ones discussed. Perhaps this is a good overview or refresher for those already familiar with Lacan's work, but for the beginner, it is useless.

Like many, I have struggled with Lacan's "own" words in English translation, sensing ideas of importance that are lost because a) Lacan intentionally obfuscated his ideas to make the very points he wrote about, b) French linguistic play doesn't translate into English, & c) translators vary in quality, in part depending on their audience (e.g., cultural studies, which often misconstrues Lacan as a postmodernist). This book is a wonderful introduction, although I suspect it is of greatest value to someone like myself who has already attempted to fathom Schema L with frustration.
For the beginner, I suggest making a try at Lacan himself especially the Seminars, for example, Seminar XI: The Four Fundamental Concepts of Psychoanalysis. After enduring one or two of these, come to this book, and then return to Lacan, who should now seem much more illuminating and witty. You may even understand why Lacan seemed so frustrating to you, which goes to his essential points about what language does for the sense of self.
Another strategy is to read any number of works by Slavoj Zizek (for example, Looking Awry, Everything You Always Wanted to Know about Hitchcock), who can slice and dice popular culture in a fun way, all the while with a very lucid understanding of Lacan's ideas. It helps to have one or two videos of Hitchcock handy as you do so.

When you need an introduction to Lacan, buy this and forget the rest. This book has at least three merits. First, the author is an orthodox lacanian psychoanalyst. This advantage could not be overstated. So many books titled so-called "Introduction to Lacan" are written by non-professional (e.g. professors of French, Cultural Studies or literary critic) with some dubious leanings and irredeemable confusions. Those books are rather personal accounts than good introductions for beginner and of no use to understand one of the most difficult writers of all time. Darian Leader's book is different. This book was written by lacanian professional rather than self-appointed "interpreter" of Lacan and supervised by Jacques-Alain Miller, the successor of Lacan. This fact makes the book the most faithful and reliable introduction to Lacan. Second, this book explains the clinical significance and origin of great Lacanian terms, e.g. repetition, sinthome, lalangue, so on. The result is that the approach makes it easy to understand. This is why other books by non-psychiatrist could be by no means competitors. Third, this book is written by exceptionally clear language and aided by intelligent graphics. Clearity is not a Lacanian virtue, but this book makes a immensely satisfying exception.