This program is awesome! A few things should be noted though: a) workouts take longer than 24 minutes! That's the time for the actual HIIT circuits, but there is also a 10 minute warm up and 10 minute cool down routine. b) you're expected to work out 5 days a week, not 3. Thursdays are cardio of your choice and they recommend "active recovery" on Tuesdays and weekends. This is a proven way to protect your body from injury and soreness, just know that the "3 days a week" selling point is a lie. c) it is not as beginner-friendly as it claims- do not hesitate to do the 4 week pre-training at the beginning of the book! I'm a relatively healthy, active, and fit 28 year old and thought I didn't need it- I was wrong.That said, I'm on week 3 of the regular program and am already seeing results despite not changing my diet. I'm not always able to complete workouts fully due to knee issues, but even doing some incomplete workouts has changed how I look and feel. Exercises are simple and easy to follow and there are descriptions of each move in the back of the book if the workout page is not clear enough. You can also find all of the exercises on youtube if you need further instruction. Workouts can be HARD and I'm usually pretty sore after, but I have so much more energy and am excited to work out for the first time in my life! The book is visually engaging and easy to use, and workouts are varied enough that I imagine you could go through it multiple times without getting bored.As others have mentioned, you could easily find all of this on pinterest or youtube, but having it planned out for you is really helpful for people like me who don't know much about fitness and don't have time or motivation to search for exercises and formulate a plan. All the figurative legwork is done for you so you can focus on the literal legwork!