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# Acknowledgements

It has now been over ten year since the publication of my book, _Domain-Driven
Design, Tackling Complexity in the Heart of Software_ (or "The Big Blue Book",
as some people have taken to calling it). In that decade, the fundamentals
discussed in the book haven't changed much, but a lot has changed about how we
build software. DDD has stayed relevant because smart and innovative people have
shaken things up repeatedly. I want to thank those people.

Let me start with Greg Young, Udi Dahan and the people inspired by them, for
CQRS and Event Sourcing. These are now quite mainstream options for the
architecture of a DDD system. This was the first successful big departure from
the narrow view of architecture inherited from the turn of the century.

Since then, there have been several interesting technologies and frameworks that
had a goal of making DDD more concrete in implementation (among other goals of
their designers), with varying degrees of success. These include Qi4J, Naked
Objects, Roo, and others. Such experiments have great value, even when they
don't gain wide adoption.

I also want to thank the people and communities that have revolutionized our
technical ecosystem in recent years in ways that make DDD much more fun and
practical. Most of these people have minimal interest in DDD, but their work has
benefited us tremendously. I'm particularly thinking of the freedom NoSQL is
bringing us, the reduced syntactical-noise of new programming languages (some
functional), and the relentless drive toward lighter technical frameworks and
unintrusive, decoupled libraries. The technology of a decade ago was complicated
and heavy, and made DDD even more difficult. There is bad new technology too, of
course, but the trend is good. So I extend a special thanks to all those who
have contributed to this trend, though you may never have heard of DDD.

Next, I want to thank those who have written books about DDD. The first book
about DDD after mine was by Jimmy Nilsson. With one book, you have a book. With
two, you have a topic. Next, InfoQ published _DDD Quickly,_ which, because of
its brevity, its availability as a free download and the reach of InfoQ, gave a
lot of people their first taste of the topic. The years went by, and there were
many valuable blog articles and other short-form writings. There were also
specialty books such as _DDD with Naked Objects._ And I particularly want to
thank the indispensable Martin Fowler, who has helped to clearly communicate the
concepts of DDD as well as often providing the definitive documentation of
emerging patterns. Just last year, Vaughn Vernon published the most ambitious
book since my own, _Implementing Domain-Driven Design_ (which some seem to be
calling “The Big Red Book”).

I feel a kind of despair over the inevitability that I will leave out many
people who made significant contributions, and I am genuinely sorry about that.
Let me at least give a blanket thank you to the people who have pushed DDD out
into the public view and to those who have pushed DDD into quiet corners of
organizations. It takes thousands of champions for a software philosophy to have
any impact.

Although this is the first print edition of the DDD reference, the earliest form
actually predates the publication of my 2004 book. On the advice of Ralph
Johnson, I extracted the brief summaries of each pattern and used them in
workshops, with each pattern being read aloud by attendees followed by
discussion. I used those documents in training classes for several years.

Then, a few years after my book was published, Ward Cunningham, as part of his
work on a patterns repository, proposed to a few authors that we put short
summaries of our patterns into the Creative Commons. Martin Fowler and I, with
the agreement of Pearson Education, our publisher, did just that, which opened
up possibilities for derivative works, such as this one.

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Thank you all.

Eric Evans, June 2014