If you legally own the books (via Kindle or other platforms) and want to store a personal copy on your Google Drive for convenience, here is the legitimate workaround:

The Portable Document Format (PDF) is the gold standard for digital piracy and sharing. Unlike proprietary formats like Amazon’s Kindle format (.mobi or .azw3) or EPUB, a PDF is universally accessible. It works on a laptop, a smartphone, a tablet, and an e-reader. It preserves the layout of the page. By searching for "PDF," the user is signaling that they want a file that is easy to read, easy to transfer, and requires no special software.

Malicious users often disguise malware, spyware, or ransomware as book files.