Compressed archives ( .rar , .zip ) from unofficial sources are common vectors for viruses. Always scan such files with VirusTotal before opening.
A book file (EPUB/PDF) inside a RAR should be small (1–5 MB). If it's much larger, it may contain executable malware. El secreto del marques.rar
There is a popular romance story titled El secreto del marqués by user maria de los angeles , involving a governess and a widower. Compressed archives (