Legal advice covers information in a whole host of subjects which people in a variety of situations may have need of. While it doesn't go into as much depth as the other subject categories do, if you're unsure about where to start, start here.
Laws constantly hold people to account, and the various corporate rules and regulations also hold organisations to account for their actions. Whether you're a big business or a small one, you need to make sure you have a solid understanding of laws which concern you.
Civil law sometimes isn't looked at as being on the same level of seriousness as criminal law, and that's fair enough, but a lack knowledge and an improper defence (and a proper offence) can give financially crippling results for the loser of a civil suit, so it still needs to be taken seriously.
Criminal law is the main area of law where under no circumstances should you go it alone. A solid legal defence is needed for every interaction you have with police and prosecutors, but it is also valuable for people to know exactly what to do in these situations, which you can find out here.