The 'Falling Kingdoms' series by Morgan Rhodes is one of those epic fantasies that hooks you from the first book. If you're diving in, I'd recommend starting with the core series in order: 'Falling Kingdoms', 'Rebel Spring', 'Gathering Darkness', 'Frozen Tides', 'Crystal Storm', and 'Immortal Reign'. That’s the main six-book arc, and it’s a wild ride—political intrigue, magic, and characters you’ll love or love to hate. After that, there’s a spin-off duology, 'A Book of Spirits and Thieves', which expands the world but isn’t essential to the main plot. Some fans read it alongside the later books, but I think it’s better to finish the core series first to avoid spoilers.
Personally, I binged the main books back-to-back because the cliffhangers are brutal. The spin-offs are fun, but they feel like a bonus rather than a must-read. If you’re the type who loves every crumb of lore, you could slot 'A Book of Spirits and Thieves' after 'Frozen Tides', but it’s not a game-changer. The main series is where the heart is—Cleo, Magnus, and Jonas’s stories are just too good to put down.