Flight Research: Problems Encountered and What They Should Teach Us (NASA SP-2001-4522) is Monograph in Aerospace History Number 22. Flight Research was written by Milton O. Thompson with a background section by J.D. Hunley. The text of this monograph originated as an untitled rough draft that Thompson wrote in approximately 1974 (before his death in 1993). Hunley has edited this insightful work and provided some explanatory background for readers who are not so familiar with what is now known as NASA's Dryden Flight Research Center in Edwards, California. Thompson was a flight engineer and a test pilot on programs such as the X-15 and the lifting bodies.

Humans to Mars: Fifty Years of Mission Planning, 1950-2000 (NASA SP-2001-4521) is Monograph in Aerospace History Number 21. Humans to Mars was written by David S.F. Portree. Mars has long held a fascination for those interested in astronomy and spaceflight and over the last half century, a great number of plans have been devised to send astronauts to Mars. Daunting logistical and physical problems still remain, however. How long would it take to get there? How would we carry the necessary supplies? After surviving a long journey, what would astronauts do once they arrived on Mars? In addressing such important questions, Portree looks at a representative sampling of the many humans to Mars plans.

The Aeronautics and Space report of the President, Fiscal year 1999 Activities, is now available in hard copy form and on-line, at http://history.nasa.gov/presrep99/home.html on the Web.

Interested readers may obtain a copy of any of these three publications by sending a self-addressed 9x12" envelope with appropriate postage for 15 ounces (typically $3.95 within the U.S., $5.05 for Canada, and $11 for overseas -international customers are asked to purchase U.S. postage through an outlet such as www.stampsonline.com) to the NASA History Office, Code ZH, Washington, DC 20546. Please send one envelope for each publication requested.