A good starter book if you are looking to commence a journey of self-development / improvement and have no idea where to start...... this is the place or if you have already been on this journey (even with a few false starts) you will find some key reminders of the basics.
This book will help you to construct a good foundation on how to achieve more with less effort.
Especially if you are not an avid reader then you will find Peter's writing style is fluid, conversational and humoristic, for those that are not generally readers this is a book well worth picking up as it is not hard work and for those avid readers probably it is less than a couple of hours of light reading to gain some great reminders.
Peter covers many of the basics such as; Beginning with the end in mind and writing it down, Prioritize - Say "No", 80/20 rule, Think-Plan-Prioritize-Focus, Capacity Planning less 20%, Good Influencers - 5 people / 6 degrees of separation, Brick Walls and what to do about them, but you will have to read the book if you are not familiar with these concepts.
If however, you are someway down the road on a personal journey of self-development, personal efficiency and effectiveness etc., then you may find the content a little light and most of the concepts already very familiar. If you are looking for something complementary but possibly more intense in its depth of content or radical in its thinking then, you may want to consider alongside this Stephen R. Covey's: The 7 Habits of Highly Effective People by Stephen R. Covey (Paperback - 4 Jan 2004) or Ricardo Semlers - The Seven-Day Weekend: A Better Way to Work in the 21st Century by Ricardo Semler (Paperback - 5 Feb 2004) or some of Ken Blanchard's work alongside many others.
This is a good starter and easy reading on a journey of self-development.