This novel is quite different from what I have read by Heinlein, that is the Lazarus Long saga, the novels where any of the Rolling Stones appear somehow, Starship Troopers, et cetera. It shows a most grounded engineering side of Heinlein and seems to be written in quite a nonchalant mood. It reads pretty easily and smoothly flows.
I actually recommend it if you have nothing to do on a rainy weekend or a long trip. You can easily finish it in less than 8 hours.
This book is still under copyright law and not part of the public domain. You have to get a copy or an e-copy. Mine cost $290 TWD, which was around $8.50 USD at the time. Those were some nicely spent TWDs.
Other books I've read