A book titled Pilot's Inflight Reference Handbook is a compilation of an aviation professional’s notes and rules of thumb that he collected over the years. In 1998 two pilots ask the author what they should have done after getting lost on an IFR flight. It had been some years since they had gone thru instrument training. This book is the answer offered to their request.

There are volumes and volumes of data available to pilots but you could never carry all of that with you on a flight. One solution is this little pocket-sized handbook which, in the author’s opinion, has the stuff you need when that other stuff hits the fan.

An excellent buy at $9.70 per each book  plus shipping.