Copies of The Sign of Four have been added to the current CheerUp.Fun Free eBook Collection. The first 100 people to sign up (new collection as of March 1) should receive a free copy added to their Kindle Library. To sign up, click this link, and follow the prompts at the Amazon page. Once you have joined the CheerUp.Fun Free eBook Collection, as recommended books are selected and shared during the month, they will be added to your Kindle Library.
You can change your settings / leave the Library at any time through your Amazon account. You will find books under the Manage Content / Devices Option, on your Content Tab, and the settings tab has a section for "Change your Whispercast Membership". Next to Organization Cheerup.Fun are options to change device or opt-out.
Many of the books written about on Cheerup.Fun are available in Kindle Unlimited, are you a member?