Having read many biographies and autobiographies, I have concluded it is harder to write an autobiography than a biography. For when one writes one’s own autobiography, one is sorely tempted to aggrandize oneself by inflating one’s own achievements and downplaying one’s own
shortcomings. Howsoever selective, one is also easily tempted to write far too much — and also tempted to flatter oneself; or, alternatively, to put oneself down.
On the other hand, biographers writing about other people — often betray their own bias. Too, they cannot possibly see the whole of the life of the person they are writing about — from the perspective of the person concerned. (Whatever that might be worth!)