Bill Gates schemed to take shares in Microsoft from his co-founder during the early days of the software company following his partner's treatment for cancer, according to a new memoir by the billionaire co-founder, Paul Allen, The Wall Street Journal reported Wednesday.

The allegation was part of a critical portrait in the book of Gates, with whom Allen formed a friendship in grade school that evolved into one of the iconic partnerships of American business. The book, "Idea Man: A Memoir by the Co-founder of Microsoft," was scheduled to go on sale April 17. A draft of the memoir was viewed by the WSJ and an excerpt of the book appeared on Vanity Fair's website early Wednesday.

The book gives a revisionist take on some details of Microsoft's history and the relationship between Gates and his former partner, the two of whom were long viewed as cordial if not close friends. The book created a rift between Gates and Allen, said people who know both men. In the book's acknowledgments section, Allen thanked Gates along with 17 other people for "general and logistical assistance."

The book was "a very balanced portrayal of their relationship," said David Postman, a spokesman for Allen. "Paul clearly values the input and the ideas and energy of Bill Gates."

"While my recollection of many of these events may differ from Paul's, I value his friendship and the important contributions he made to the world of technology and at Microsoft," Gates said in a written statement.

Allen's unflattering account of Gates in the book was already making waves within the tight circle of early Microsoft alumni, with several people who know both men privately expressing confusion about Allen's motivations for criticizing his old business partner and questioning the accuracy of Allen's interpretation of certain events. Allen, for instance, put himself in meetings that people familiar with the meetings said he never attended.

In one case, Allen visited Palo Alto, Calif., to help woo a computer scientist who would later become one of the Microsoft's most important programmers. People familiar with the meeting said it was Gates who made the visit. Postman said that he was not aware of any errors in the book.

In the book, Allen also positioned himself as the spark of many of Microsoft's most important ideas, playing down Gates' role in some cases. Woven throughout the book was a bitterness Allen expressed for not receiving more credit for his work throughout his career and more shares in Microsoft.