K&R "The C Programming Language" is a classic. If you're serious about learning C this book should definitely be in your collection. It's the book most C programmers have cut their teeth on over the past several decades, written by the guys who wrote the language itself. (Though go for the most-current ANSI version). If you already know basics of programming methods from Python or JS, you'll be able to handle this book. Make sure to do the exercises!

Beyond that, it would depend what you're hoping to do with C. Eg, Linux kernel hacking? Optimized Python numpy routines?

There also are some recent books that focus on writing 'modern' and also safer C code, particularly with regard to usage of pointers. There are some links on Amazon and O'Reilly that may be helpful (I haven't read any so can't give recommendations)