&gt; Some terms (opcode, ISA) are not really explained (except in the glossary) before they are used and there are perhaps too much detail in the expense of the bigger picture.<p>I feel like if you want to get into serious reverse engineering (beginner or not), you should have a basic understanding of computers. Both of these terms are <i>extremely</i> basic, from that perspective.<p>Opcodes are what Assembly instructions correlate to. ISA just refers to the architecture of the CPU (x86 vs ARM)...e.g. WHAT opcodes&#x2F;asm applies.