Pablo Picasso was alternately angelic and cruel, generous and stingy, says biographer John Richardson, whose first volume on the life of the Spanish-born artist is being published this month.

Richardson, an art historian and Picasso protege, said in an interview in the February issue of Vanity Fair that the artist was "a strange mixture of exhibitionism and secretiveness.""It's so difficult to write about Picasso because you always have to see the other side of the coin," Richardson said. "He was an angelic friend, but also demonic and cruel. He was incredibly generous, but also unbelievably stingy.

"I've tried to demolish the legends because the real story is so much more interesting," Richardson said. "Usually people who have these diametrically opposed qualities are in a loony bin, but somehow Picasso managed to contain all this within himself and put it to such fantastic use."

The four volumes of "A Life of Picasso" are to be published by Random House. The first volume covers from the artist's birth in 1881 to the creation of "Les Demoiselles d'Avignon," painted in Paris in 1906. Picasso died in 1973 at age 91.