Crowley biographer Martin Booth asserted that Crowley was "self-confident, brash, eccentric, egotistic, highly intelligent, arrogant, witty, wealthy, and, when it suited him, cruel."[229] Similarly, Richard Spence noted that Crowley was "capable of immense physical and emotional cruelty".[230] Biographer Lawrence Sutin noted that Crowley exhibited "courage, skill, dauntless energy, and remarkable focus of will" while at the same time showing a "blind arrogance, petty fits of bile, [and] contempt for the abilities of his fellow men".