| title | ISBN-13 | year of publication |
|---|---|---|
| Character Code | 978-1-880674-01-7 | 1991 |
| Color Code | 978-1-880674-00-0 | 1987 |
| Color Your Future: Using the Character Code to Enhance Your Life | 978-0-684-86571-3 | 2000 |
| The People Code: It's All About Your Innate Motive | 978-1-4165-4230-8 | 2007 |
D,. H.. · P. H. · P. Hartman · Ph.D. · T D · T.H. · T. Hartman · T.P · Taylor Hartman · Taylor P · Taylor Ph.D.
Color Code Intl · Scribners · Simon & Schuster