Marietta B. Zacker is the co-owner of Gallt & Zacker Literary Agency and a specialist in children's book illustration — she represents illustrators and author/illustrators almost exclusively, with a particular passion for authentic, emotionally resonant, and inherently diverse visual storytelling.
In brief
Zacker's focus is narrow and intentional: she is building a list of illustrators and author/illustrators of children's books, not prose-only authors — querying her with a text-only manuscript is almost certainly a mismatch.
Her philosophy centers on emotional authenticity over lesson-teaching; she wants visuals and stories that make readers feel something, with the child's or young adult's perspective firmly at the center — not the adult creator's agenda.
As co-owner and WNDB agent liaison, she has deep institutional roots in the diversity-in-publishing movement — authentic, inherent representation is a baseline expectation, not a bonus feature.
Her Caribbean background (born in Puerto Rico to Panamanian and Cuban parents) informs her aesthetic; voices that reflect the full breadth of the world — not curated, comfortable bubbles — are what she gravitates toward.
Submissions were closed as of November 2023; her own form is the authoritative source for current status, and writers should verify before querying.
Lately
Her agency bio and submission guidelines make clear that her current focus is exclusively on adding illustrators and author/illustrators of children's books — a deliberate and narrow scope she has maintained consistently.
What Marietta is looking for
This is Zacker's stated and exclusive current focus. She is actively adding illustrators and author/illustrators — not prose-only authors — to her client list. She seeks portfolios and illustrated stories that generate genuine emotional responses: joy, wonder, grief, humor, any feeling at all. The work must center the perspective of the child or young adult, not the creator. Diversity is non-negotiable, but it must be organic and authentic rather than topical or performative. She is particularly drawn to creators who have not previously felt there was space for their stories in the industry.
Picture books are a core part of her children's book focus, but she is seeking author/illustrators — creators who bring both text and art. A standalone picture-book writer (without illustration) is not what she is currently building toward. The visual component is essential.
Illustrated and graphic novel formats for children fall within her scope, provided the visual storytelling is central. She values work across the BIPOC, LGBTQ+, and Caribbean literary traditions, as well as humor, literary fiction, and action/adventure — all filtered through a child-centered lens.
Not the right fit
On Marietta's list
Taste fingerprint
How to query Marietta
Verify the submission form is open before doing anything else — it was closed as of November 2023 and her own form page is the only authoritative source for current status.
Illustrators and author/illustrators only: if you are a prose-only writer, Zacker is not the right match at this time. Your query must include or foreground visual work.
Lead with the emotional experience your work creates, not its themes or lessons. She responds to art and story that make readers feel — articulate what that feeling is and how your visual work achieves it.
Demonstrate that diversity is structural and intrinsic to your work, not a layer applied on top. Avoid framing your manuscript as 'a diverse take on X' — let the specificity of your characters and world speak for itself.
If a colleague or contact referred you, confirm with them before adding their name to the referral field — Zacker explicitly notes this in her guidelines.
Submit to only one Gallt & Zacker agent at a time. If you've already queried another agent at the agency, wait for a response before approaching Zacker.
Allow up to six weeks for a response, and understand that she may occasionally need longer — she builds in that flexibility herself and notes it openly.
Her Caribbean background and Latina identity are genuine parts of her editorial lens. Stories rooted in those cultural experiences may resonate particularly well, but authenticity always outweighs demographic proximity.