For the last few years, I have been busy writing new books that have since been published:
Rockets of Tipu Sultan was published on Amazon Kindle Book (ebook) in 2014
Aerodynamic Noise: An Introduction for physicists and engineers, Springer Aerospace Technology, 2013
High Temperature Gas Dynamics: An introduction to physicists and engineers – 2nd Edition, Springer Aerospace Technology, 2014
Airbreathing Propulsion: An Introduction, Springer Aerospace Technology,, 2012
Rocket Technology (in progress, manuscript due December 2016)