The main problem you face when you're attempting to lift the lid on what makes Linux tick is knowing where to start. It's a complicated stack of software that's been developed by thousands of people. Following the boot sequence would be a reasonable approach, explaining what Grub actually does, before jumping into the initiation of a RAM disk and the loading of the kernel. But the problem with this is obvious. Mention Grub too early in any article and you're likely to scare many readers away. We'd have the same problem explaining the kernel if we took a chronological approach.