It's tricky to make a recommendation. You say "booklet", which implies a small project, but I assume if it's successful you won't stop at one. Here's the thing: no matter what software you use, you're faced with a significant investment of time learning to use the application, and from a practical standpoint I consider that a very important consideration. I'm pragmatic. What will get the product out the door at the quality I need in the shortest amount of time is what I will always go with, even if (as has happened) I have to learn a whole new application to get there.
Several other answers here give you some insights. I don't want to detract from them.
Here are my suggestions, with the reasons why, so you can make your own judgment.
For authoring the text, use the word processor you're most familiar with. It doesn't matter much what it is, because its sole purpose is to get the text together. The shorter the learning curve, the better. If you're a whiz with a good code editor, that's going to work for you better than Scrivener, Scribus or Word if you have to learn them before you can get up to speed. (If you're already up to speed on LaTeX, you're miles ahead of the curve, but it doesn't sound like you are.)
For layout, I would highly recommend InDesign, not because it's the best possible tool (Framemaker or LaTeX would make some tasks simpler, especially if you were going deeply into long textbook authoring), but because it will get the job done and the effective and useful learning resources at your disposal are easily ten times what's out there for other possibilities. InDesign is a fairly steep learning curve, but LaTeX and Framemaker are, frankly, a cliff. The sheer quantity of excellent training resources for InDesign, and the huge and active community that surrounds it, make it my "Editor's Choice" for a newcomer to page layout.
GREP styles in InDesign are easy for anyone half-way familiar with regular expressions, and you can build a library of queries and styles based on regex which are portable from project to project. Do them once, and you have them forever.
Quark Xpress is a powerful layout program. It's been overtaken by InDesign because it has less support, doesn't have the intensely powerful integration of the Creative Suite, and its training resources are now completely overshadowed by InDesign. I don't personally know anyone who's switched from Quark to ID who would ever switch back.