Downloading copyrighted Macmillan books without payment is illegal in Spain, Latin America, the US, and the EU. Internet service providers (ISPs) can issue warnings, and in some countries, fines range from €300 to €10,000.
Open Library (a sister project of Internet Archive) allows you to "borrow" digital copies of newer Macmillan books (1970–2010) for 1 hour at a time. This is a legal, DRM-protected loan, not a permanent download. Total cost: $15–50 USD, depending on the title
The Internet Archive has thousands of digitized Macmillan books from the 1920s–1960s. These are legally downloadable because their copyright has expired in the US. Search for "Macmillan" + "ebook" + "texts." Total cost: $15–50 USD
If you absolutely need the latest version of a specific title (e.g., Ready for C2 Proficiency), follow this legal workflow to get a downloadable, offline file: there are two exceptions:
Total cost: $15–50 USD, depending on the title.
If you drop the requirement "última versión" (latest version), you can legally download older Macmillan editions. Copyright expires 70–95 years after publication, but Macmillan textbooks rarely enter the public domain. However, there are two exceptions: