Series
There are 6 books in the Locke & Key series.
Published between 2008 and 2016. The publication order differs from the reading order — both are below.
Locke & Key is Joe Hill and Gabriel Rodríguez's horror-fantasy comic, collected in six volumes beginning with Welcome to Lovecraft. After their father is murdered, the Locke children move into Keyhouse, a family home full of magical keys — and something in it wants them.
All 6 books total 1,982 pages.
The Books Oracle — track the series you are partway through, and see what to read next.