Ex-Nokia CEO Jorma Ollila says the former No 1 mobile phone company made several mistakes at its peak, including failure to predict changing customers' needs.
In his autobiography, which translates from the Finnish as An Impossible Success, Mr Ollila concedes that after 2001 the Finnish company was unable to sustain its role as the main innovator in the wireless industry.
Several of its models flopped and it failed to sense popular trends such as folding clamshell handsets and touch screen models.
Mr Ollila said at the launch of his book in Helsinki on Thursday that Nokia became "painfully aware" that its mobile platforms lagged behind US software and the challenges posed by the iPhone.
He also described the planned sale of Nokia's smartphones and services to "arch rival" Microsoft as "dramatic and brave".