Are there any books to understand Philosophy of Vedic Samhitas? We have many introduction books for Vedanta but not Vedas. Any suggestions??
https://archive.org/details/the-secret-of-the-veda-sri-aurobindo/mode/2up This may help . This book is written by Sri Aurobindo and titled "The Secret of the Veda" . However if you want translation of samhitas , I must warn majority of verses have deep meanings and are not to be understood literally . https://archive.org/search.php?query=dr+tulsi+ram .Here you will find commentary/interpretation of each verse of all 4 vedas . Of course it is not perfect( Dr. Tulsi Ram has excluded Dasrajna war from Rig veda) but still very much good .
There are a huge number of books. However, I would recommend the books by R. L. Kashyap or Kapali Sastri, who was a great scholar, who studied under Ramana Maharshi, Aurobindo and Kavya Kanta Ganapati Muni. They have a trust that sells these books. They have a complete 22 volume set that covers all four vedas, including sanskrit, transliteration, translation and interpretation but you can buy each samhita separately also.