"Where the Crawdads Sing" is a novel written by Delia Owens that has gained immense popularity and acclaim. While it's not a traditional advertising campaign, the book's success can be attributed to a combination of factors that collectively contribute to its status as a bestselling novel. Here's an overview of how "Where the Crawdads Sing" became a bestselling novel:

1. Compelling Story: At the heart of the novel's success is a compelling and engaging story. It's a coming-of-age mystery and romance novel set in the marshes of North Carolina, blending elements of nature writing, crime fiction, and a love story.

2. Word-of-Mouth and Critical Acclaim: "Where the Crawdads Sing" received positive reviews from critics and quickly became a favorite among readers. Positive word-of-mouth recommendations from readers played a significant role in its success.

3. Book Club Selection: The novel's themes and discussion-worthy content made it a popular choice for book clubs, leading to further exposure and discussion among readers.

4. Social Media and Online Communities: The book gained traction on social media platforms, with readers sharing their thoughts and recommendations. Online book communities and platforms like Goodreads also contributed to its visibility.

5. Bestseller Lists: As the book gained popularity, it started appearing on bestseller lists, including The New York Times Best Seller list, which further fueled interest and sales.

6. Author's Background: Delia Owens, the author, is an experienced wildlife scientist and nature writer. Her background and expertise in nature added authenticity to the novel's natural settings and wildlife descriptions, making it even more appealing to readers.

7. Film Adaptation: The announcement of a film adaptation generated additional buzz around the book, motivating more people to read it before the movie's release.

8. Book Cover and Marketing: The book's cover design and marketing efforts by the publisher, Putnam, played a role in attracting potential readers.

9. Book Recommendations: Prominent book influencers, reviewers, and celebrities recommended the novel, amplifying its reach and appeal.

10. Emotional Resonance: The novel's emotional depth and memorable characters resonated with readers, making it a book that people wanted to discuss and recommend to others.

While "Where the Crawdads Sing" did not have had a traditional advertising campaign, its success demonstrates how a combination of factors, including compelling storytelling, word-of-mouth, critical acclaim, and online communities, can propel a book to bestseller status and make it a cultural phenomenon.