Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Great book worth the read if you train or want to start training on your own with dumbbells!

Dumbbell Training for Strength And Fitness is a well-written and illustrated guide to safe and effective dumbbell training. If, like me, you've been training with dumbbells for years and prefer it to other training methods, this book will expand your knowledge base on dumbbell training and provide a ton of tips on technique you would typically get only from a very knowledgeable personal trainer. If you are just getting started, most importantly, this book will walk you through the proper technique for dumbbell training. I cannot stress enough, especially with dumbbells, the need for "safe" training for longevity and "effective" training to achieve the results that motivate you to keep training. Great book worth the read if you train or want to start training on your own with dumbbells!