MicroZed Chronicles (Vol. I) – https://fpgasite.wordpress.com/2016/08/13/the-microzed-chronicles-free-fpga-book/
Free Range VHDL – https://fpgasite.wordpress.com/2016/07/24/free-range-vhdl-free-book/
Altera's FPGA for Dummies - https://fpgasite.wordpress.com/2016/03/25/fpga-for-dummies-free-book/
Xilinx's High Speed Serial IO - https://fpgasite.wordpress.com/2016/04/07/high-speed-serial-io-book/
FPGA prototyping book - https://fpgasite.wordpress.com/2016/06/23/prototypical-fpga-prototyping-free-book/
FPGA's now what - https://fpgasite.wordpress.com/2016/04/14/fpgas-now-what-free-book/
The Zynq book - https://fpgasite.wordpress.com/2016/06/28/the-zynq-book-free/
Introducing Spartan 3E and VHDL - https://fpgasite.wordpress.com/2016/07/09/introducing-the-spartan-3e-fpga-and-vhdl-free-book/