More on なら

Previously I learned that なら can be used as a contextual "if" type word, although it can't be used universally to express an if statement. As Tobira says, "it's used when the speaker supposes that something is the case or is true and makes a statement, suggestion, etc. based on that supposition.

の is added before なら if the supposition is based on hearsay, i.e., if the speaker has heard what they're saying from someone or somewhere else.

One difference between なら and たら, another "if" form: The sentence structure [Sentence 1 + (if word) + Sentence 2] is often used. In the case of  なら, the action or event in Sentence 1 does not need to take place before that in Sentence 2. However, when using たら, the action in Sentence 1 does have to take place before that in Sentence 2. An example:

本を読むなら、電気をつけなさい。
If you're going to read a book, turn on the light.

Since the "turn on the light" action would have to take place before the "read a book" action, the たら "if" form could not be used here.

車を運転するのなら、お酒を飲んではいけません。
If it's true that you're driving a car, then you must not drink.

日本語なら、一日中に勉強出来るよ。
If it's Japanese, then I can study all day long.

日本に行くのなら、JRパスを買っておいた方がいいですよ。
If you do go to Japan, then you should buy a JR pass (in preparation).

部屋でゴミがたくさんあるのなら、捨てなきゃよ。
If there really is a lot of trash in your room, you need to throw it away.