When I was young, my favorite picture book was 'Fletcher and Zenobia,' written by Edward Gorey and illustrated by Victoria Chess. It's long out of print now, but its mix of macabre humor and 1960s psychedelia made it a perfect children's book for the times.

Rick Riordan’s quote reflects on his fond memories of the picture book "Fletcher and Zenobia", written by Edward Gorey and illustrated by Victoria Chess. He recalls that the book was a favorite from his childhood, appreciating its macabre humor and how it resonated with the cultural atmosphere of the 1960s. The book's unique combination of dark humor and the colorful, experimental vibe of psychedelia made it stand out as a children's book that captured the spirit of the time.

The mention of macabre humor in the book indicates that it contained elements of the gothic or morbid, which was often paired with whimsy and absurdity, typical of Edward Gorey's work. This type of humor is unconventional for children's literature, as it blends dark themes with lightheartedness, making it both eerie and funny. The mix of these elements made it particularly appealing to the more curious and adventurous children of the time.

Riordan also connects the book’s appeal to the 1960s psychedelia, a cultural movement known for its experimental art, music, and a sense of alternative reality. The psychedelic elements of the book reflected this broader cultural shift, with its vibrant, imaginative style and its playful engagement with surreal themes. This connection to the 1960s gives the book an even more unique and timely significance in the context of its publication and the era’s cultural shifts.

In essence, Riordan’s quote speaks to the lasting impact of "Fletcher and Zenobia" on his childhood, illustrating how it merged macabre humor with the psychedelic influences of the era, making it a perfect fit for the 1960s. The book’s distinctive qualities, combining dark and whimsical elements, set it apart from other children’s literature of the time, and its influence remains a fond memory for Riordan.