It is our pleasure to present this special issue of Heat Transfer Engineering with a selection of papers presented at the 20th National and 9th ISHMT-ASME Heat and Mass Transfer Conference, held January 4-6, 2010 in Mumbai, India. The conference was jointly sponsored by the Indian Society of Heat and Mass Transfer (ISHMT) and the American Society of Mechanical Engineers (ASME) and was held at the auditorium of the Nuclear Power Corporation of India Ltd., at Anushakthi Nagar, Mumbai, India. The conference local organizer was Indian Institute of Technology Bombay.