**Acknowledgements**

I want to express my gratitude to Dr. Peter Mazur, "The Father of Modern Cryobiology," who passed away on December 30, 2015, at the productive age of 88. Dr. Mazur continued mentoring fellows and conducting studies into his final year and for the last decade provided us critically important insights into vitrification, specifically the relative effects of warming on oocyte and embryo survival and viability. As he completed the scientific journey he had started more than 60 years earlier, he was able to clearly demonstrate to us the relative importance of warming over cooling rate. Thank you for all that you taught us that made these technological advance‐ ments possible. And finally, thank you for making it so transparent that "The rate of warming must be equal to or exceed that of the cooling rate, if we are to optimize survival." I am so grateful to have had the opportunity to have had a couple of memorable phone conversations with you in 2015. Godspeed Dr. Mazur and rest in peace, knowing that your scientific contri‐ butions will educate future generations.
