While I admire both The Art of Computer Programming and Structure and Interpretation of Computer Programs, I thought I'd mention two other books in answer to the first of your two questions.

J. Glenn Brookshear's Computer Science: An Overview, 10th ed. is intelligently organized and quite well written. It also has worthwhile chapter review problems and useful bibliographies at the end of each chapter.

David J. Eck's The Most Complex Machine: A Survey of Computers and Computing might be worth looking at. If I remember correctly, Eck received his PhD in mathematics from Brandeis University in 1980.