There are multiple sources available online where "I Know Why the Caged Bird Sings" by Maya Angelou can be found in PDF format for download or reading. Some sources include Scribd and other literary websites offering free PDFs or excerpts. If a direct downloadable PDF of the full book is sought, it may be accessible on some document-sharing platforms such as Scribd (which may require an account or subscription) or other reputable ebook libraries. There are also educational and thematic summaries and analyses of the book available in PDF form. For example:

• Scribd has a PDF document titled "I Know Why The Caged Bird Sings" available for download or reading, which likely includes the full text or significant excerpts.

• Other sites offer retold or summarized versions for educational purposes in PDF.

• There are also literary study guides and analyses in PDF format that could be useful.

If the goal is to find the full official text, the best approach is to use legitimate ebook platforms or purchase the book through authorized sellers to respect copyright. Would access to a specific kind of PDF (full text, summary, study guide) be preferred?