Iain M. Banks died in 2013. His work is still under strict copyright. If you see a website offering "The complete Iain M. Banks Culture Series free MOBI download," it is either a virus or an illegal upload. Banks’ estate deserves your support. The quality of the illegal scans is often terrible—missing italics (crucial for Mind dialogue), OCR typos, and broken formatting.
Here is the legal, practical advice:
Collection of short stories, including one set on 1977 Earth. Use of Weapons Complex non-linear story of a mercenary agent. Iain M. Banks - The Culture Series -mobi- epub-