Quotes from book
Boy

Boy: Tales of Childhood is an autobiographical book by British writer Roald Dahl. This book describes his life from birth until leaving school, focusing on living conditions in Britain in the 1920s and 1930s, the public school system at the time, and how his childhood experiences led him to writing as a career. It ends with his first job, working for Royal Dutch Shell. His autobiography continues in the book Going Solo. An expanded edition titled More About Boy was published in 2008, featuring the full original text and illustrations with additional stories, letters, and photographs.

“When writing about oneself, one must strive to be truthful. Truth is more important than modesty.”
Source: Boy: Tales of Childhood

“We all have our moments of brilliance and glory, and this was mine.”
Source: Boy: Tales of Childhood

Edna St. Vincent Millay, in "First Fig" from A Few Figs from Thistles (1920); said to be a motto Roald Dahl lived by.
Misattributed
Variant: My candle burns at both ends;
It will not last the night;
But, ah, my foes, and, oh, my friends —
It gives a lovely light.
Source: Boy: Tales of Childhood