Harry Browne won no small measure of fame when he wrote this book, essentially foreseeing the coming dollar devaluation by Nixon (with the final untethering of the dollar from gold).
This book was recommended as having some superb chapters explaining the nature of money, inflation, fractional-reserve banking, etc. I would agree that it was excellent in that regard. The rest of the book was great too, discussing as it does some strategies for investing depending on the anticipated economic climate (recession vs. devaluation vs. depression vs. inflation vs. hyper-inflation, etc). When he wrote the book, it was still technically illegal to own gold, so some of his advice and topics covered may be somewhat narrower than what is needed today, where gold is legal obviously. Still, a fantastic primer on financial and economic concepts. I would also suggest, as a means to understanding gold, money, banking, etc., a reading of Murray Rothbard's book "What Has Government Done To Our Money / The Case For A 100% Gold Standard."