I have a few copies of the first book, and a few years ago contacted Alan Clements with additional questions, which he kindly answered. He is now retired, and spends his time doing photography, especially traveling to New York.
Great book, wish I'd picked up one 20yrs ago. Also picked up copy of 1st edition which covers some stuff not in 3rd edition (68010 difference to 68000).
Got a 68EC030/68681/68230 on way from China to build SBC from book. Odd that 030 is cheaper than 020. Suitable PGA socket for 68030 is proving elusive so far.