We finished Book 3 a fair few weeks ago, Book 3 (1987-1988) is the biggest book yet, 370+ pages, over 300 reviews.
http://www.spectrumgamesbible.co.uk/
Book 4 (1989-1990) will be out early December, then its Book 5 (1991-1993) and finally Book 6 (1994-200x) which will feature all the homebrew...