Acknowledgements

I would like to express my gratitude, first of all, to my colleague Elizaveta Tarasova, for her insightful and all-important remarks while I was preparing this book. I am also deeply grateful to Antonio Lillo Buades, Eliecer Crespo Fernández, and Félix Rodríguez González, who were kind enough to comment on a preliminary draft of the manuscript. Their recommendations were invaluable, and any remaining infelicities, of course, are entirely my own responsibility.

My thanks also go to Ronnie Lendrum for reviewing the manuscript and for making it more approachable to readers. Also, my gratitude goes to Susana López, who did a wonderful job with designing the figures used in the book.

And last but not least, I wish to thank my university colleagues and friends Reme Perni, Sara Prieto, and Irene García for their moral support and companionship.