Complex sentence: Apple spokesman Steve Dowling admitted that Apple helped the authors in writing the books, as the company felt it could do more for its founder and Tim Cook was not happy with Walter Isaacson's official biography, "Steve Jobs".
Split into simpler sentences: Apple spokesman Steve Dowling admitted that Apple helped the authors in writing the book, as the company felt it could do more for its founder. In addition, Tim Cook was not happy with Walter Isaacson's official biography, "Steve Jobs".