Real Estate? Pfui! Invest in Books

I have two volumes of the old O. Carm. breviary which I got for one euro each about two years ago. I've been looking for the other two volumes ever since. I haven't seen any copies of any of the volumes until today when I chanced upon the two volumes I already happen to have. One was priced at $65 and the other at $120.

I'm saving the best for last, though. I've been searching for a copy of "The Royal Irish Rangers' Standard Settings of Pipe Music" for something over 20 years. In fact, ever since I decided not to buy the copy in my hand because it was $35 and that wasn't quite in the budget that day. I haven't seen a copy for sale since. Until today: $585.86

I wonder if I can invest my I.R.A. completely in books?