Madonna's Nanny to Pen Tell-All Book

"Extra's" learned Madonna's former nanny is currently shopping around a book that could blow the lid off Madge and husband Guy Ritchie's private life.

Entertainment Weekly has seen the book proposal from a woman claiming to have been the caregiver of Madonna's children.

Insiders say the juicy read is full of intimate information about Madonna's marriage, and the real reason Madonna and Guy decided to adopt Baby David!