Don't combine with poet "Robert Hass" - even if some of his works occasionally turn up on this page because of typos - since there are authors who really are named "Robert Haas".
(1) Robert Haas (1948- ), Eat to Win, nutritionist
(2) Robert Haas, Special Effects in Photography
(3) Robert Haas (1886-1960), Die Musik des Barocks, Austrian musicologist
(4) Robert Haas, I Dreamed of Flying Like a Bird, National Geographic photographer
(5) Robert Haas, The Haunted Mind, English teacher at University of South Florida