The first book is a replica journal, like the earlier Equestria Girls Tell-All, this time from the eyes of Pinkie Pie in the MLP: The Movie universe. Besides the Mane 6 we also see Tempest Shadow on the cover, so she'll likely play an important role in this book.
The other book also features Tempest Shadow on the cover, together with Twilight Sparkle. This book is named "The prequel to My Little Pony The Movie", and is probably suitable to read before watching the movie, hence the release date of August 1st.
Below we have all information available regarding the two books, including links for pre-orders on Amazon:
Release Date: August 29, 2017
Age Range: 7 and up
Grade Level: 2 and up
Series: Replica Journal
Publisher: SFI Readerlink Dist
Release Date: August 1, 2017
Age Range: 8 - 12 years
Grade Level: 3 - 7
Series: Beyond Equestria (Book 1)
Publisher: Little, Brown Books for Young Readers
While Princess Twilight Sparkle is busy with preparations for Equestria's first ever Friendship Festival, a foreign power is planning its attack. The Storm King has sent his most trusted lieutenant, Tempest Shadow-a Unicorn with a broken horn-to scout her former home. But Tempest wasn't always eager to do a villain's bidding...
Find out how a sweet and kind pony became one of the most feared throughout the land and get ready for My Little Pony: The Movie, coming to theaters October 6, 2017! Join Twilight Sparkle, Rainbow Dash, Pinkie Pie, Applejack, Rarity, and Fluttershy on the adventure of their lives!