I'm illustrating a book. I'm using Photoshop to add effects, my text is in Illustrator and all of the illustrated pages live and will print from InDesign. My book size is 10.25 x 10.25 inches, and all images are set to 600dpi and CMYK color. I intend to produce an e-book and a print book.
My process is:
Save Asinto a Photoshop EPS file.
Save Asto PDF.
Is this the right way of doing this, or is there a better way?
The optimum way to do what you're seeking is to create the book in InDesign, as you mentioned, but...
1) The text should all be done in InDesign, not Illustrator or Photoshop. Your file size will be much smaller, you'll have a much easier time editing the text, and your printed product will be better. Illustrator and PS are hugely powerful, but page layout is not what they are made for. InDesign is made for this. Use the right tools for the right jobs.
2) If you're creating images in Photoshop, you can them Place (import) them into InDesign using Cmd+D (on a Mac, Ctrl+D on PC)... but 300dpi (CMYK) is the optimum resolution. 600 is overkill, and will only make your file size bigger, which can lead to much longer processing time at the printer. There are differing opinions on which format is best, but .psd, .tif, .jpg or .eps are all fine.
3) I'm assuming your illustrations are done in Illustrator... if so, save those as either .ai or .eps, then Place (import) them into your InDesign file as well.
4) When the book is complete, you can export (Cmd+E on Mac, Ctrl+E on PC) a hi-res (images at 300dpi) PDF for your printed version, with printer's marks, and a lower res (images at 72 or 96dpi) pdf for your eBook version... an eBook by nature will be viewed only on screen, so 300dpi is unncessary.