Calisthenics is a form of exercise consisting of a variety of movements, such as running, standing, pulling, pushing, stretching etc. using your bodyweight as resistance, sometimes performed rhythmically and with minimal equipment. Bodyweight training can be used to increase muscle mass, losing body fat increasing cardiovascular capacity and also help improve athletic performance. Using your bodyweight as resistance for exercises is an important part of bodybuilding and other sports. This form of training has always been around, the army uses Calisthenics to train and assess their troops.
Why do calisthenics?
FULL BODY TRAINING 
A large part of Calisthenic movements involved using the entire body as a complete unit. As a simple example is performing push up. While you do a push up not only your chest muscles work, but also your arms, shoulders and core. This develops great coordination and helps burn more calories, since using several muscles in one movement requires more energy.
Most of the calisthenics moves are compound exercises therefore your body needs more oxygen, which leads to harder heart and lung work. That is why body weight training is so beneficial for our cardiovascular system and burning fat.
YOU DO NOT NEED EXPENSIVE EQUIPMENT
Bodyweight training can be performed at home, at the park and if you have space even at the office! Over time doing Calisthenics will cost you far less than going to the gym. There is no need for complicated machines or sharing a busy gym floor equipment. You will also save time by cutting down on travelling to the gym.
VARIED WORKOUTS
One problem for many people working out at the gym is that most people do the same workouts day in day out. If you do calisthenics you can chose from hundreds of activities. You can combine everything you want and increase the resistance at your will.
FLEXIBILITY 
A lot of the movements incorporated into a calisthenic workout requires some degree of flexibility. Most exercise using your body as resistance, will likely involve using a full range of motion. Take the squat for example, it is much easier to get down all the way with hips going below the knee joint, without having a heavy loaded barbell across your shoulders. This increases mobility in the hip, knee and ankle joints in a safe and natural way.
CONCLUSION
The ideal strength training regime would typically include both a mixture of Bodyweight, Barbells, Dumbells, Kettlebells etc. It would be recommended, when possible that beginners learn how to use their own body as resistance, to learn the proper body mechanics for functional movements. Always warm up sufficiently before performing any type of workout and cool down immediately afterwards with some light stretching to help with muscle soreness, stiffness and overall recovery.