Energy is the life force of our planet – without it, life would not exist! Energy makes things move and grow, or can change things. Everything we consume, use or eat is energy or has energy in it.
A library book has used energy or had energy used to create it and transport it to where it is so, although it contains only a small amount of energy, there has actually been a huge amount of energy used to bring it to where it is.
It's the same with the chair you sit on and the shampoo with which you wash your hair. So energy is embodied in everything that we use.