First of all, we would like to thank all our friends and family. Without their support, writing this book would have been an even more difficult task. Thanks for accommodating our schedules and taking care of our children in order to free up time for us to focus on writing. You're wonderful, and part of this book is also yours.

We are three Spaniards who wrote a book in English, so if you'd guess our English is far from perfect, you'd be correct. Luckily for us, Edd Mann has supported us with the language since the beginning. He's not just a great collaborator but also a great friend, and we owe him a huge thanks. The final review was done by the professional copy editor Natalye Childress. She has done a great work rewriting our words to make them understandable. Thank you so much. Our book is easier and more enjoyable to read.

A group of PHP developers in Barcelona defends what we call el camino del rigor, or the path of rigor. It existed before the craftsmanship movement, and it means to struggle with everything stacked against us in order to build exceptional things in an exceptional way. Two particular developers and friends from that group are Albert Casademont and Ricard Clau, both of whom are extraordinary people committed to the community. Thank you so much for helping with the revision process. Your contributions have been incredibly valuable.

We would like to thank every developer who has worked with us in the companies where we've applied Domain-Driven Design. We know you've been struggling when learning and applying these concepts. Some of you weren't so open-minded at the beginning, but after using the basic building blocks for a while, you became evangelists. Thanks for your faith.

Our book was for sale from the moment we put the first chapters on Leanpub. Early adopters who bought the book in its beginning stages gave us the much needed love and support to get this done. Thanks for the motivation to keep going.

Thanks also to Matthias Noback for his foreword and feedback on the book. The end result is better because of his contributions.

A special mention to Vaughn Vernon — not just because his work was an incredible source of information and inspiration for us, but also because he helped us find a good publisher, gave us valuable advice, and shared ideas with us. Thanks so much for your help.

Last but not least, we'd like to express our gratitude to all the people who have reported issues, made suggestions, and otherwise contributed to our GitHub repository. To all of you, thank you. You've helped us make this book better. More importantly, you've helped the community grow and helped other developers be better developers. As Robert C. Martin wrote in his book, Clean Code: A Handbook of Agile Software Craftsmanship, "You are reading this book for two reasons. First, you are a programmer. Second, you want to be a better programmer. Good. We need better programmers." So thanks to Jordi Abad, Jonathan Wondrusch, César Rodríguez, Yannick Voyer, Victor Guardiola, Oriol González, Henry Snoek, Tom Jowitt, Sascha Schimke, Sven Herrmann, Daniel Abad, Luis Rovirosa, Luis Cordova, Raúl Ramos, Juan Maturana, Nil Portugués, Nikolai Zujev, Fernando Pradas, Raúl Araya, Neal Brooks, Hubert Béague, Aleksander Rekść, Sebastian Machuca, Nicolas Oelgart, Sebastiaan Stok, Vladimir Hraban, Vladas Dirzys, and Marc Aube.