Schwaber’s first book, Agile Software Development with Scrum, is more of a reference book than a how-to. It describes what Scrum is, but not so much the nuances of how to use it. The second book includes a reference section in the back that pretty much recaps the first book. So, start there. If a pass through the reference section makes sense to you, then proceed directly with the second book. Otherwise, pick up the first book as well and use it to get up to speed.

If you are not yet up to speed on XP, the quintessential tome, Extreme Programming Explained: Embrace Change (2nd Edition) by Kent Beck, is still the best starting place. I’d recommend reading that before reading up on Scrum. As you do, just keep in mind that Scrum essentially replaces and expands upon the XP “planning game.” Don’t skip reading about the planning game. Just understand that if you have questions about how the planning game works in the real world, hold those questions until you get to Scrum.

In Clean Code, Martin doesn’t just name the best practices we should all be following. He explains the reasoning behind each one and gives names to the concepts. Just as the idea of software design patterns revolutionized the way we think and talk about software architecture, Martin’s exploration of day-to-day coding habits gives us a smarter way to think and talk about that.

Case in point: Clean Code kicks off with the practice of giving your objects meaningful names. One aspect of this is that good names do not require anyone who might read your code in the future to have to perform any “mental mappings.” Here’s an example of this that I came across just the other day.

var ld = new LoginData();

Look carefully, that’s a lower-case L. At first glance, it looks like a capital I, as in “ID,” as in “identifier.” I don’t know how long I spent confused about how a class constructor could be returning an identifier when reading through this code for first time. Maybe ten or fifteen seconds? Time in which I was completely distracted from understanding the rest of the code, having pushed that problem onto the stack, as it were, in order to first solve this mini-problem.

Even without the I vs. L confusion, using an abbreviated variable name meant that whenever I came across it, I had to keep reminding myself that it stood for an instance of LoginData. That may not seem like a big deal, but we humans only have so much stack space before we run out of short-term memory. When a program is full of one- and two-letter variable names that must be continually translated mentally, it leaves no room for thinking about the actual problem that the program is trying to solve.

All of this could have been avoided if the name was spelled out to begin with, so I changed it (using the automated rename refactoring tool in my IDE):

var loginData = new LoginData();

“One difference between a smart programmer and a professional programmer is that the professional programmer understands that clarity is king. Professionals use their powers for good and write code that others can understand.” ~ Robert (Uncle Bob) Martin

Martin could have just said, “don’t use abbreviations in variables names, because you’ll make the reader translate it in his head every time he reads it,” and that would have been terrific advice alone. But what he really gives you is a deep understanding of the key principles involved, so that you won’t need to memorize a bunch of arbitrary coding standards in order to write cleaner code. Instead, you’ll be armed with a few simple, understandable principles to guide you, with clean code being the natural outcome.

Clean Code is a must-read for everyone in the software profession — from college freshmen on up to CTOs — especially anyone who finds himself out of work in this economy (or worried about the possibility). Learning to write clean code, and thus to write more valuable code, is probably the single most effective thing you can do for yourself. Programmers are expensive resources. The work we produce is costly. It’s up to us to treat it with the respect it deserves, to try and make it as valuable as possible, and to maintain that value as long as possible.

I’m helping out with a study group for “Head First Design Patterns,” which just finished chapter 6. On the whole, it’s a pretty good introduction to software design patterns — way more accessible than the seminal work by the Gang of Four; however, the examples sometimes make my head hurt. I can’t imagine what they’re doing to the heads of the beginners in the group. Coming up with decent examples is the hardest thing to do in expository writing, and I certainly give the authors an E for effort in creativity, but I wish they had been a little less concerned with making their examples “hip” and a little more concerned with making them appropriate.

To wit, the whole pizza store analogy in chapter 4 (to illustrate factory method and abstract factory) is flawed. For one thing, that’s just not the way you’d model a pizza business in any actual software that I can imagine. For another, the differences between a New York pizza factory and a Chicago pizza factory are too subtle/trivial to make for an effective illustration of why you would need to subclass anything (much less use a factory to manage the subclasses). A much better example, as everyone in my group agreed, would have been an application that needs to offer up a consistent set of functionality to users who are accessing it in wildly different ways: one’s in a web browser on a desktop, another is running a cell phone app, another is using a touch-tone phone, and yet another is using a voice-activated headset. All the client code knows is that, for example, it needs to ask a multiple-choice question and obtain the answer. It’s up to an abstract factory to provide the client with a set of classes that can do that, in the context of the selected user-interface, in whatever way is necessary.

To a lesser degree, the Starbucks coffee example at the beginning of the book suffers from the same too-hip-to-be-effective syndrome, although I do think that the remote-control example for the Command pattern in chapter six is dead on.

For any novice who is reading this book without the benefit of a study group, I highly suggest that you find at least one other programmer who is experienced in design patterns to explain why/if/how the examples are lacking.