Illustrator vs InDesign for laying out a simple picture book?

Would you have any reccomendations on when you've left "modest?" My books will be approximately 32 pages.

You start to exceed "modest" when your document:

• Needs over 100 pages (Illustrator's Artboard limit).
• Contain a large number of (often oversampled) linked raster images. (Many, if not most, users very often needlessly oversample raster images.)
• Contain a large number of very complicated vector graphics. (Think highly-detailed metro road maps or something.)
• Contain large amounts of long threaded text stories.
• Contain a large number of live raster effects.

The document you've described so far does not sound like that. But you've provided very little information about the actual content. ("Picture" doesn't tell anyone anything; doesn't even indicate whether you're talking about raster images or vector graphics.) So long as your "pictures" are reasonably optimized, you'll most likely be fine. Nothing you've described so far would cause me to hesitate to build the whole document in a drawing program—but that's based on how I envision what you've described, in the context of how I would typically build it. Without knowing the specifics, one can really only advise you to start building the file and see (learn from experience). If performance becomes a hindrance, you may be making the 35 pages too complicated to work efficiently in a single drawing program file.

You can easily and quickly test. Simply build one Artboard containing the typical kinds and number of objects. Duplicate that Artboard 34 times. See if working in the file becomes burdensome, performance-wise.

And one last question: are there text styles you can set up in Illy" and is tehre anything like Master Pages?

That's two questions. ;-)

Yes, Illustrator provides both Character- and Paragraph-level Styles. (See the documentation). It's handling of Styles is worse than InDesign's, but probably tolerable for what you've described.

Illustrator's text handling in general is sub-standard (no proper Paragraph Rules functionality; no in-line graphics; wonky Styles inheritance behavior; stupid selection behavior), but one tolerates that stuff whenever working in Illustrator, regardless of page count.

There are no "Master Pages" per se. But you can set up one Artboard containing the objects you would ordinarily populate "master pages" with, and duplicate the Artboard as many times as needed. Then start adding page-specific content. As in InDesign, you can utilize Layers and or object locking so that working on top of the "master page items" does not become cumbersome.

Also see the documentation and acquaint yourself with Symbols. You can create all the objects you would consider "master page items," store them as a Symbol, and simply position Instances of that Symbol on all your pages. A Symbol is actually stored in the document only once, and is just referenced for its additional positions (and other transformations). Edits to a Symbol automatically cascade to all its Instances, much like master page items in a conventional-wisdom page-layout program.

JET