Perhaps include a section on open educational resources (OER) that cover similar topics. If the Ghosh book isn't available legally in PDF, recommending other textbooks that are OER could be helpful.

In that case, the best approach is to direct users to official sources or libraries. Also, note if the user is in a region where the book is public domain, but that's a complex check.

Another thought: The user mentioned "verified." They might have encountered issues with pirated copies circulating online, which can be risky (malware, viruses) and legally problematic. The feature should emphasize safe and legal avenues.

Need to structure this information in a clear, step-by-step manner. Maybe start with checking the publisher's website for free downloads (if available), then move to libraries, and then suggest purchasing if all else fails. Also, include warnings about the dangers of pirated versions.

I should also consider the user might not be in a country where the book is readily available. Translating the feature into multiple languages might help, but that's beyond the scope here.

By implementing this feature, users receive a clear, ethical pathway to access educational content while respecting legal boundaries.

Another possible feature is a guide on how to request the book through interlibrary loan services if they have access to a public library.

So, the challenge is to help users find legitimate sources for the book. Maybe users aren't aware that the book is available for free in some formats or through libraries. Alternatively, they might have a legitimate need to access a digital copy but are unsure where to look.