* Word processor: This is the most common and versatile option. Microsoft Word, Google Docs, Pages (for Mac), LibreOffice Writer are all excellent choices. They allow for easy formatting, spell checking, and saving your work.
* Note-taking app: If you prefer a simpler, less formal approach, a note-taking app like Evernote, OneNote, or Bear could work. These are great for brainstorming and organizing your thoughts before writing a more polished report.
* Mind-mapping software: Programs like MindManager or XMind can help you visually organize your ideas and the structure of your report before you start writing.
Ultimately, the best program depends on your personal preference and the level of formality required for your book report. A simple word processor is usually sufficient.