One of my favourite authors in embedded system design is Prof Valvano at the University of Texas at Austin. His popular embedded design courses on his UT webpage and edX are fantastic learning materials for anyone interested in this field.
In fact he was the author of one of the very first books I’ve read on embedded systems back in 2000 (Embedded Microcomputer Systems).
I’ve recently purchased the entire series of his embedded design books for ARM Cortex M. The first volume starts with a comprehensive introduction to the very basics of digital design and MCUs. The 2nd and 3rd volumes dig deeper into the details of Cortex M4, MSP430, TI Launchpad boards and RTOS. If you’re a fan of TI MSP430 series and looking for practical examples based on Launchpad development boards, the 2nd and 3rd volumes are must-haves.