Eu vejo que esta é uma pergunta antiga ... mas talvez este post ainda mais antigo no ebookreadersoftware.wordpress.com responda:
Blog Post diz:
Any website that sells ebooks in Adobe’s DRM-protected format will tell you ahead of time that you must use Adobe Digital Editions. If you skip over all those instructions, and you don’t install the software you are told that you need, then of course your computer won’t know what to do with this .acsm file.
As I mentioned above, the .acsm file is NOT supposed to contain the entire text of a book. It is not the ebook at all. It is a small file that manages the download of the ebook through Adobe’s content server.