string theory - What is Kaku's equation about?

When Michio Kaku talks about science he often likes to refer to string theory and sometimes to his equation which looks like this (not sure if wrote right):

$$L = \Phi^\dagger[i\partial_{\tau}-H]\Phi + \Phi^{\dagger} \ast \Phi \ast\Phi .$$ It appears to me like some field theory Lagrangian with an interacting and a free part but I have no idea what it actually describes.

Can all of string theory really be summarised in this equation? Can someone give a brief description?