The rules of baseball don't change much and are relatively brief compared to other sports. And Major League Baseball has always had them online, although they exist in a fairly unwieldy pdf format now. However, they have not always been able to sort through.
Even with an index, (which baseball now calls Rule 11), it can be hard to find out just where to look for information on when a game is suspended and when it is terminated. Or what the rules for obstruction by a fielder are. Or what obstruction is as opposed to interference.
The authors, who are baseball fans and professionals in design, do a great job of making the rules of baseball look attractive and interesting. Or as least as interesting as the rules for fielder's interference can be.
The Rules of Baseball are codified in sections called "The Batter" or "The Pitcher" or "Starting and Ending Game." But rules applying to all three of these players or situations can appear in different sections of the rulebook.
So, Formosa and Hamburger, reorganize the rules and put them in to 15 chapters and use some nice graphics to explain some of the more complicated rules, such as obstruction (an area of the rule book that Miguel Tejada missed out on) or batting out of order.
If you read the book from cover to cover (which the authors say that you shouldn't do, but I did because I'm that sort of person), you will realize that there is duplication. But that makes sense because a chapter on fielders would also have some corresponding section in a chapter on baserunners.
I only had a few quibbles with the book.
For starters, I think citations to the rule numbers used would be helpful or at least be more helpful if you are using the guide to settle an argument. However, I would assume that the authors/designers didn't want to gum up the book with lots of references to things like Rule 8.06(d).
I also think that the rules are covered well, but I disagree with the contention that managers or pitching coaches can run out to the mound to speak with their pitcher if it is the offense who requests time and the manager or coach leaves before the ball is put in play. I've never seen that at any level of play. And I can't find it in the rule book and I would assume that with the desire for baseball to speed up games that any such trip by a manager to the mound would be looked at askance.
However, I think the book does do a great job of explaining the balk rule (as well as you can since calling a balk is often more of an art than a science) and there is a very good depiction of the infield fly rule and why it exists that should satisfy even the most casual of fans.
The book would work for hardcore fans, but I think it would work best for someone who is just starting to become a fan. It would work best while watching a game and could be handier to use than having some guy who pretends to be a know-it-all (such as me) sit next to you and pontificate on the intricacies of why runners get one base (and the batter too) when a catcher stops a pitch with his mask in his hand.