Not sure it qualifies as an introduction to any particular field within tech, but for a general deep dive into the inner workings of computers: Code: The Hidde

Not sure it qualifies as an introduction to any particular field within tech, but for a general deep dive into the inner workings of computers: Code: The Hidden Language of Computer Hardware and Software I just love this book! It was a joyous adventure of discovery the first time through. Subsequent reads always yield new insights.