This was a very passable little introductory book to existentialism. The author is clearly very familiar with the subject; and seemingly enjoys it as well. This isn't the kind of book that you traditionally read from cover to cover I suspect (however, I did). Regardless, anyone interested in existentialism or anyone taking a basic modern philosophy class couldn't do themselves wrong by buying this book.
Just as the title states, the book is a short overview about key ideas in existentialism. Arranged in alphabetical order from themes like "the absurd", "the nothing", to philosophers like Kierkegaard, Sartre, and Nietzsche. It's a kind of CliffNotes of the 20th century philosophy.