Unless you're just starting out in MTB and have bought yourself a cheap and perhaps second hand knockabout, or if you happen to be a die hard retro gear fanatic, the brakes you will have on your bike will bear little resemblance to the old school cantilever systems you would have found on the first models to be commercially produced in the early 1980s.
The basic principal of the design whereby a cable pulling on two cantilevered arms on either side of the wheel pressed the brake pads to the rim in order to stop the wheel from turning remained largely unchanged until the introduction of the disc brake in the early to mid 1990s. There were subtle changes, such as the 'U' break, now widely used in BMX, or the 'V' break, which can still sometimes be found on entry level mountain bikes, but nothing which radically altered how the brakes actually functioned.
Disc brakes are now all but ubiquitous, and professional standard bikes will be equipped with advanced versions which utilize technology comparable with that used in motor sport. Probably the sole disadvantage of this technology compared to the cantilever brakes of old is that it is a good deal more sophisticated in its engineering, and therefore a fair bit more difficult to repair and maintain.
Here then is CRC Nukeproof Mechanic Carl Geeson with his guide on how to fit a new set of Formula Brake pads. Some of these components are extremely small (this is precision engineering after all), but, provided you don't lose any of them, the principals all sound very logical and straightforward. So watch and learn – a few more of these and you too could be an expert MTB mechanic in no time.