To Leticia and Alexa, thank you for making my life much more joyful than I could have imagined.

A mi madre, con todo el amor, admiración y respeto. Gracias por guiarme con el mejor de los ejemplos y por ense?arme a nunca dejar de aprender, a trabajar duro y a vivir con honestidad.

I want to dedicate this book to my parents, Abdul Rashid and Sherbano, and sisters, Tasneem and Lubna. Thank you all for your encouragement on every small step that I took forward. Thank you mom and dad for all the sacrifices and for always believing in me. I also want to thank my seniors, for their mentorship, and my friends and colleagues, for supporting me over the years.