Reading Order

Reading Order 

Changeling Chronicles World

While each series can be read on its own, if you want to read the books chronologically without any spoilers, here's the order I recommend:
Legacy of Flames
The Changeling Chronicles
The Gatekeeper's Curse
The Thief's Talisman
The Hemlock Chronicles
Heritage of Fire
The Gatekeeper's Trials
The Gatekeeper's Fate

 

Alternatively, the series can also be read in publication order without any spoilers:
The Changeling Chronicles
Legacy of Flames
The Thief's Talisman
The Gatekeeper's Curse
The Hemlock Chronicles
Heritage of Fire
The Gatekeeper's Trials
The Gatekeeper's Fate

For a more detailed timeline, see below. ​

Note: The events of the Hemlock Chronicles and the Thief's Talisman series take place at the same time but in different locations so there's no overlap between the two series. Likewise, there is a time skip between Books 2 and 3 in the Heritage of Fire trilogy with the ending overlapping with the final Hemlock Chronicles book, but each series can be read separately without major spoilers.

Faerie Killer (The Changeling Chronicles prequel)
Adrift (Legacy of Flames prequel)
Alight (Legacy of Flames 1)
Arise (Legacy of Flames 2)
Aflame (Legacy of Flames 3)
Legacy of Flames Epilogue
Ignite (Heritage of Fire 1)
Inflame (Heritage of Fire 2)
Faerie Blood (The Changeling Chronicles 1)
Faerie Magic (The Changeling Chronicles 2)
Faerie Realm (The Changeling Chronicles 3)
Faerie Wrath (The Changeling Chronicles 4)
Faerie Curse (The Changeling Chronicles 5)
Faerie Hunt (The Changeling Chronicles 6)
Faerie War (The Changeling Chronicles 7)
Hereditary Magic (The Gatekeeper's Curse 1)
Hereditary Curse (The Gatekeeper's Curse 2)
Hereditary Power (The Gatekeeper's Curse 3)
Witch's Shadow (The Hemlock Chronicles 1)
Mortal Heir (The Thief's Talisman 1)
Witch's Soul (The Hemlock Chronicles 2)
Iron Bound (The Thief's Talisman 2)
The Gatekeeper's Curse Epilogue
Exiled Queen (The Thief's Talisman 3)
Witch's Spirit (The Hemlock Chronicles 3)
Witch's Secret (The Hemlock Chronicles 4)
Witch's Sacrifice (The Hemlock Chronicles 5)
Inferno (Heritage of Fire 3)
Hidden Crown (The Gatekeeper's Trials 1)
Hidden Court (The Gatekeeper's Trials 2)
Hidden Power (The Gatekeeper's Trials 3)
The Last Gatekeeper (Short Story)
Wild Magic (The Gatekeeper's Fate 1)
Wild Hunt (The Gatekeeper's Fate 2)
Wild Fury (The Gatekeeper's Fate 3)

Celestial Marked

The Celestial Marked Series is a five-book series, intended to be read in this order:

Celestial Magic (Celestial Marked 1)
Celestial Fire (Celestial Marked 2)
Celestial Ashes (Celestial Marked 3)
Celestial Shadows (Celestial Marked 4)
Celestial Storm (Celestial Marked 5)

Parallel Magic World

The Order of the Elements series and the Parallel Magic trilogy take place side by side, in parallel (pun intended). 

 

For the best experience, I recommend reading the books in this order:
Thief of Souls (Order of the Elements 1)
Touch of Death (Order of the Elements 2)
Trial of Shadows (Order of the Elements 3)
Cage of Fire (Parallel Magic 1)
House of Fire (Parallel Magic 2)
Deal of Darkness (Order of the Elements 4)
Tower of Fire (Parallel Magic 3)
Element of Life (Order of the Elements 5)