The 15th edition. 32 volumes.
He also got a set of Hot Wheels toy cars, and those plastic, orange tracks you could link together to make all sorts of loops and bends and dips.
He sat in his room and stacked up volume after stiff-spined volume on top of each other and laid out complex Hot Wheels tracks over the Britannica. The die-cast toys sped over "Volume 8: Menage-Ottawa" and ended up curving around a loop to "Volume 29: United-Zoroastrianism."