If I have a blank index.html file is there any way for someone to get past it to see other files?

Example: www.bookingapple.com

Thanks!

They would have to know the exact names of the pages. But if they did they could get around that.

Right. I'm just checking to confirm that there's not some techie way to get a view of the folders and files without knowing their names.

Google and other search engines may crawl and index your site. Searching for terms on these 'hidden' pages will return a link to them. Your best bet is to prevent Google from crawling the pages by setting up a robots.txt file. Find info on the robots.txt here: The Web Robots Pages