99 Bottles of OOP. 2 ed

 It turns out that everything you need to know about Object-Oriented Design (OOD) can be learned from the "99 Bottles of Beer" song.

 Well, perhaps not everything, but quite certainly a great many things.

 The song is simultaneously easy to understand and full of hidden complexity, which makes it the perfect skeleton upon which to hang lessons in OOD. The lessons embedded within the song are so useful, and so broad, that over the last three years it has become a core part of the curriculum of Sandi Metz’s Practical Object-Oriented Design course.

 The thoughts in this book reflect countless hours of discussion and collaboration between Sandi, Katrina Owen, and TJ Stankus. These ideas have been battle-tested by hundreds of students, and refined by a series of deeply thoughtful co-instructors, beginning with Katrina. While none of the authors have the hubris to claim perfect understanding, all have learned a great deal about Object-Oriented Design from teaching this song, and feel compelled to write it all down.

 Therefore, this book, now in its second edition. We hope that you find it both useful and enjoyable.