To my chagrin, he apparently died in 1988 - it's not clear if he was 54 or 55. (I'm PRETTY sure that information was not available when I posted birthday greetings for him, five years ago.)
http://www.solanocf.org/uploads/pdf/Ray_Cruz-Rev_2-7-13.pdf
(brief memorial, with photo)
http://www.lib.usm.edu/legacy/degrum/public_html/html/research/findaids/DG0240f.html
(brief bio, photo, partial booklist)
https://www.google.com/search?hl=en&site=imghp&tbm=isch&source=hp&biw=1680&bih=913&q=%22ray+cruz%22+illustrator&oq=%22ray+cruz%22+illustrator&gs_l=img.3..0j0i24.1032.1032.0.1389.1.1.0.0.0.0.41.41.1.1.0...0.0...1ac.1.18.img.LAEvJ_d9iQI
(illustrations, some covers)
http://blogs.slj.com/afuse8production/2012/06/18/top-100-picture-books-8-alexander-and-the-terrible-horrible-no-good-very-bad-day-by-judith-viorst-illustrated-by-ray-cruz/
More titles in chronological order:
The Storybook Cookbook, 1968 (Carol MacGregor)
White Rose & Ragged Staff (Elizabeth Seifert)
Wizard of Washington Square (Jane Yolen)
Horrible Hepzibah, 1970 (Edna Mitchell Preston)
Jennifer Takes Over PS 94 (Mary Lystad)
Where Do I Belong? (M. Jean Craig)
Alexander & the Terrible, Horrible, No Good, Very Bad Day (Judith
Viorst)
The Electric Radish & Other Jokes, 1973 (Susan Thorndike, compiler)
Winter Hut, 1973 (Cynthia Jameson)
Gorilla Did It, The, 1974 (Barbara Shook Hazen)
Woman with the Eggs, The, 1974 (by Jan Wahl & Hans Christian Andersen)
Alexander, Who Used to Be Rich Last Sunday, 1980 (Judith Viorst)
Lenona.