Questions & Answers

Frequently Asked Questions

Everything you need to know about Hidden Library

For Readers

What is Hidden Library?

Hidden Library is a newsletter featuring curated book deals in the Mystery genre. We send promotions several times per week featuring free, discounted, and regular-priced mystery books carefully selected by fellow mystery enthusiasts.

How often do you send newsletters?

We send newsletters every Tuesday and Friday at 10 AM Eastern time, featuring carefully selected mystery books that match your reading preferences. Occasionally, we also send additional special editions for seasonal promotions or exceptional book deals.

Is the newsletter free?

Yes, absolutely! Subscribing to our newsletter is completely free. You'll receive book deals directly to your inbox at no cost, forever.

What genres do you feature?

We focus exclusively on Mystery books, including Cozy Mystery, Traditional Whodunit, Police Procedural, Thriller & Suspense, and Historical Mystery. Other genres may be added later, but are not part of the current promotions.

Can I unsubscribe?

Absolutely. Every email includes an unsubscribe link, and you can opt out at any time with a single click. No questions asked.

For Authors

How do I submit my book?

Visit our Submit Your Book for Free Promo page and fill out the submission form. You'll need your book's cover image, retailer links, ASIN, and basic information about your book.

What genres do you accept right now?

At the moment we accept:

  • Mystery
  • Cozy Mystery
  • Thrillers

We focus on ebooks in these categories, including light and cozy reads, classic whodunnits and darker suspense. Other genres may be added later, but are not part of the current promotions.

We do not feature books containing explicit sexual content or depictions of animal cruelty/torture.

Does my book need to be free or discounted?

We prioritise:

  • free books
  • discounted books
  • special offers and limited time deals

We may occasionally feature full price titles, especially for first in series or strong launches, but free and discounted books generally perform better for our readers.

Do you accept Kindle Unlimited titles?

Yes. Kindle Unlimited titles are welcome as long as they fit Mystery, Cozy Mystery or Thrillers and comply with Amazon's KU terms.

Is submission free?

Yes. At this stage, submitting your book is free and there is no submission fee.

We are currently offering a limited number of free promotion spots while we grow the platform and audience.

Does submission guarantee my book will be featured?

No. We review all submissions carefully, but only selected titles will be scheduled for promotion. This ensures we maintain quality and variety for our readers.

How will I know if my book is selected?

We'll contact you via email if your book is selected for a promotion. You'll receive confirmation of the promotion date and all details.

Can I choose my promotion date?

During submission, you can select a preferred promotion date. However, this is a request only—we'll confirm the actual date after reviewing your submission based on availability and editorial fit.

What deal types do you accept?

We feature free books, discounted books, and regular-priced books. However, free and discounted deals typically perform best with readers.

Do you host or distribute ebook files?

No. We never host or distribute ebook files.

All promotions link to official retailer pages such as Amazon, Kobo, Apple Books and similar platforms. Readers always get your book directly from the retailer.

Will there be paid promotion options in the future?

Yes. In the future we plan to introduce paid options such as:

  • guaranteed placements
  • featured spots with higher visibility
  • special themed promotions

When paid options become available, we will clearly mark them as such and provide full details before you decide.

How can I increase the chances of my book being selected?

Some things that help:

  • a clear, professional cover that matches the genre
  • a strong and accurate genre placement (mystery, cozy, thriller)
  • a readable and engaging book description
  • a deal that is attractive to readers (free or a real discount)
  • first in series, or good entry points into a longer series

We also try to balance different styles and subgenres, for example cozy village mysteries, classic whodunnits and darker thrillers.

How often can I submit a book?

You may submit:

  • the same title again after two months between promotions
  • different titles whenever they are ready for promotion

If your book has already been featured recently, we may ask you to wait before scheduling it again. This helps keep the content fresh for readers.

Can I submit more than one book at a time?

Yes, you can. However, we may not feature all titles at once.

We may choose one or two books that seem strongest for our audience and schedule others at a later time if they are a good fit.

Do you guarantee sales, downloads or reviews?

No. We cannot guarantee specific numbers for sales, downloads or reviews.

We can offer exposure to a growing audience of mystery readers and a professional presentation of your book, but results will always depend on the book itself, the offer, timing and the behaviour of readers and retailers.

Do you accept explicit or very graphic content?

We focus on Mystery, Cozy Mystery and Thrillers that are suitable for a general audience of crime and suspense readers.

We do not accept:

  • explicit sexual content as a primary focus
  • extremely graphic violence
  • hate speech, illegal content or material that violates retailer terms

If you are unsure whether your book is suitable, you may describe the content briefly in the submission form and we will review it.

Do I need to schedule my price change before the promotion?

Yes. If you are running a free or discounted deal, please make sure:

  • the price is already active or scheduled at the retailer
  • the promo dates you give us match your retailer settings
  • the promotion is valid in the regions you select

If the deal is not active when our newsletter goes out, readers may see a different price than expected.

In which countries or stores will my promotion appear?

Our newsletter goes to an international audience, but most readers use large platforms such as:

  • Amazon
  • Kobo
  • Apple Books
  • Google Play

In the submission form, you can tell us which regions your deal applies to, for example US, UK, DE or worldwide. We may prioritise books that are available to a wider part of our audience.

How will my data be used?

We use the information you provide to:

  • review your submission
  • prepare and run promotions
  • contact you about your book and related opportunities

We do not sell your personal data. All data is processed in line with our Privacy Policy and applicable data protection laws. You can request changes or deletion of your data at any time, unless we are required to keep certain records for legal reasons.

Can publishers or agents submit on behalf of authors?

Yes. Publishers, small presses and agents are welcome to submit titles as long as:

  • they have the right to promote the book
  • they provide accurate and up to date information
  • they agree to the same terms and confirmations as individual authors

Please indicate your role in the submission form.

What happens after I submit my book?

After submission:

  • You receive a confirmation that your form was received
  • We review your book along with other titles in the queue
  • If your book is selected, we email you with a proposed promotion date and basic details
  • The promotion runs on the scheduled date and appears in the newsletter and on the site
  • If your book is not selected for a particular period, you may submit again later, especially if you have a new deal or a new cover

Content Guidelines and Promotion Policies

To keep the newsletter safe and enjoyable for readers, and compliant with retailer rules, we apply the following content guidelines.

We accept:

  • Mystery, Cozy Mystery and Thriller ebooks
  • Light, medium or dark suspense, clearly positioned for the correct audience
  • Books published on recognised retailers such as Amazon, Kobo, Apple Books, Google Play or similar platforms

We do not accept:

  • Explicit sexual content as the primary focus
  • Pornographic material
  • Extremely graphic or sadistic violence
  • Hate speech or content that targets groups based on race, religion, gender, orientation or similar characteristics
  • Illegal content or content that appears to promote illegal activity
  • Plagiarised works or books that appear to infringe on another author's intellectual property
  • Covers or descriptions that clearly misrepresent the genre or the nature of the book

You are responsible for ensuring that:

  • you hold the rights necessary to promote the book
  • your book complies with the terms of service of all retailers you link to
  • your book complies with applicable laws in the main regions where it is sold

We reserve the right to decline or remove any title that, in our judgment, does not fit our audience or violates these guidelines. This applies even after initial acceptance, for example if the cover, description or content is significantly changed.

We may also limit repeat promotions of the same title in order to keep the newsletter varied and interesting for readers.

General

How do I contact you?

For questions or support, please check our Impressum page for contact information.

Where can I find your privacy policy?

Our complete privacy policy is available on our Privacy Policy page.

Still have questions?

We're here to help! Check our Impressum page for contact information.

Contact Us