s of a deeply interconnected society. Achieving the required performance will increasingly require investigating the boundaries between the information theory, which describes the limits of the telecommunication system in terms of bit rate, and the theory of electromagnetism, which describes the physical limits to which it is subject. In order to reach this goal, it is necessary a description of the communication process at a DPL compared to Physical Layer of the OSI model that allows to relate the physical processes underlying the communication to the amount of information transmissible by the system. This suggests the introduction of a further layer underneath the physical layer, called the Deep Physical Layer. In DPL the communication process is modeled in terms of distinguishable configurations of the radiated electromagnetic field. The performance of the com- munication system in terms of channel capacity is fixed at the level of the Deep Physical Layer. It is also possible to carry out a "processing" of the electromagnetic field at the Deep Physical Layer level which allows to optimize the performance of the telecommunications system, obtaining an "intelligent DPL" environment. The solutions currently being studied for 6G based on the use of reconfigurable intelligent surfaces are an example of this approach. As last remark, this study is only one aspect of the rather complex and fascinating problem of the relationship between energy and information. In fact, the close connection between "bits and fields" shown by the DPL analysis is an indication of the existence of some important relationships between information and physics. These connections are much deeper than the simple use of electromagnetic waves in wireless communication systems and involve fundamental aspects of physics. In the famous example discussed in the Theory of Heat [80], Maxwell introduced a demon that seems capable of violating the validity of the second law of thermodynamics. Maxwell considers a box divided into two sections, connected