I often get asked how I became a bike tech. The truth is that the flying fickle finger of fate descended from Mount Everest and touched me whilst I slept, imbuing me with the ability to lay my hands on any two-wheeled, human-powered mode of transportation and cause it to rise up from the ashes in all its former glory... Or something like that. But when people ask me how to become skilled at bike repairs without getting fingered, the answer is simple: "Zinn & the Art of Mountain Bike Maintenance"
This tome is a compendium of information which will allow even the most reluctant rider to undertake repair tasks previously believed only to be performed by apron-wearing geeks at a significant impact to the wallet. For those with little experienced, it begins with a two page spread with the anatomy of a bike. Pretty much every conceivable part is labeled. It’s a good thing to know what’s what on your bike, if for no other reason than shop mechanics won't take you seriously if your "doomawhichy" won't catch after you shift the "flommergadget."
The next step is to figure out what tools you should have. Mr. Zinn (May I call you Lennard?) defines 3 levels of tool kits, a shop kit and two levels of tool kits to carry on your bike. Now, I'm going to go out on a limb here and say that a level one tool kit doesn't require a shock pump or a fork pump with a ball needle. But pretty much everything else he lists for that kit is a solid tool for the beginner (including the "noggin"!)
From there, the book goes through repairs in a generally ascending order. If you take your bike, and start from the front of the book (the early chapters are going to be pretty simple to learn from) you'll amass the knowledge for more complicated jobs. The book includes info on some parts that are more specific to individual makes and models (Grip Shift, for example). To the book's compliment, this just means that you are more likely to find the information you need to work on the model that you have.
If you were to sit down with your bike at the end of the riding season (for those of you who actually stop riding for a season) you could work your way through the book. Learning as you go and making the little tweaks and adjustments, you would be able to make your bike work as if it had been touched by the finger itself! Lennard keeps just enough humor in the pages to hold your attention without getting so silly that you lose perspective. It's a fine line and I think he walks it fairly well.
In addition to a solid primer for newbies, there is enough technical stuff in here that Zinn and the Art of Mountain Bike Maintenance comes in handy for long time techs who just need to see how to rip apart a certain type of derailleur. Hey, we can't remember everything all the time!
Be warned, that once you get to the indexes at the back, you are likely either to feel as though you are trying to memorize the periodic table of the elements, or else you'll be able to declare yourself a full on bike tech geek, ready to disassemble (and hopefully reassemble) the first bike you see!