I really enjoyed this cross-over of Pellucidar with ERB's most famous hero, Tarzan. It starts out with amazing pulp tropes - amazing inventions, Tarzan, an airship, an artic opening to the hollow earth, African tribesmen, dinosaurs, etc. Just amazing in how rich this one book was with those pulp standards.

On the downside, the recurring theme of getting lost in Pellucidar was alive and well. Thinking their friends are dead? Check. Thinking the girl you suddenly realize you love hates you? Check. Losing all your clothes and quickly adapting to a loincloth? Check.

Still, a very fun read. And it is left at a bit of a cliffhanger.