Adventures in Middle-Earth (AiME) is an RPG set in Tolkien’s world between the events of the Hobbit and Lord of the Rings. It is based on the Dungeons & Dragons 5th edition engine, and you only need the free System Reference Document to use the AiME books.
Below you can find links to Reviews of many of the AiME books.

I’ve also played Wilderland Adventures and Eaves of Mirkwood and written my comments on how I ran the adventures and what I would change.

Cubicle 7 no longer has the rights to producing the game, so there are no more supplements coming, but the books currently available are more than enough to run multiple campaigns and to build your own.

All in all, it is a fantastic and faithful low-magic merging of the D&D 5e rules and the Tolkien-universe. There are a couple of balance issues and design issues, especially at the higher levels, but nothing a creative Loremaster can’t fix.

Reviews:
Player’s Guide to Adventures in Middle-Earth
Loremaster’s Guide to Adventures in Middle-Earth
Loremaster’s Screen and Eaves of Mirkwood
Mirkwood Campaign
Wilderland Adventures
Rhovanion Region Guide
The Road Goes Ever On

Game guide:
Wilderland Adventures 1: Don’t Leave the Path
Wilderland Adventures 2: Of Leaves and Stewed Hobbit
Wilderland Adventures 3: Kin strife and Dark Tidings
Wilderland Adventures 4: Those Who Tarry No Longer
Wilderland Adventures 5: A Darkness in the Marches
Wilderland Adventures 6: The Crossings of Celduin
Wilderland Adventures 7: The Watch on the Heath