Every transistor leaks heat, every wire radiates, every clock edge wobbles. These "imperfections" are not bugs — they are physics. Side-channel attacks, fault injection, RF eavesdropping, and even why Spectre worked all start at the level of electrons in silicon. Skip this layer and the rest is magic.
This is the foundation. Before we touch a single circuit, we need to understand what we are actually pushing around inside wires. We are going to build up — patiently — from the question "what is electricity?" all the way to lasers and the quantum-mechanical reasons your flash drive forgets. Take your time. This chapter is meant to be re-read.