Pulitzer Prize winner Michael Cunningham is among the A-list contributors to “The Letter Q: Queer Writers’ Notes to Their Younger Selves” (Scholastic). Think of this anthology as the literary offspring of “It Gets Better,” the viral video campaign with a message of hope for gay youths facing bullying and homophobia. In tender letters, editor Sarah Moon and other writers pass on their wisdom about coping with discrimination, coming out, finding love, and making a life. Half the royalties from sales of the book will go to the Trevor Project, an organization dedicated to preventing suicide by lesbian, gay, bisexual, transgender, and questioning youth.