Excellent fitness book written by a Special Operations military trainer based on the principle that form follows function. He defines fitness as the degree to which a person possesses muscular endurance, strength, power, balance, flexibility, coordination, speed, and CV endurance. His premise is that the best way to change your overall health - and your physique - is to focus on the development of these 8 components of fitness. He argues that your body changes in order to give you the required skills to perform the activities demanded of it. Thus to change body composition, one needs to focus on creating new physical demands and developing new athletic skills. For this reason, he is not a fan of steady state or endurance training, which he believes in the end lead to muscle loss, a slower metabolism, and fat gain. Rather, his program is composed of short, intense, interval type workouts using compound movements that engage many muscles at once (high intensity interval training [HIIT]). He believes that these intense and brief (sometimes as short as 20 minutes) workouts build muscle, improve strength and CV performance, and increase your metabolic rate for about 48 hours after you complete the workout. Additional benefits: you can do these body-weight exercises anywhere, you don't need a gym or any expensive equipment, and there's a nearly endless variety of exercises to choose from!

One additional note - I'm training for a half marathon (and eventually a marathon) and wanted some additional advice on how to work in the necessary distance runs without losing any of the gains made through HIIT. I emailed the author (Mark Lauren) and he responded nearly immediately with friendly encouragement and links to related training forums on his website. Very helpful and appreciated!

Highly recommend this book for anyone who is serious about fitness!