A: Tantra = A system of spiritual beliefs and practices said to be derived from Sanskrit roots signifying: "body" because of its emphasis on bodily activities; "stretch" because it extends the faculties of humans; "rope" because it secures the devotee to deity; "harp" for the music and beauty of its philosophy; "interiorness" for the secrecy of its doctrine; "loom" suggesting the two cosmic principles, male and female, that make up the warp and woof of the woven fabric of the universe.
Kama Sutra = God of erotic love. Lust. Sexuality. Sutra = "Thread, A book of aphorisms."
The Kama Sutras were written by a man named Vatsyayana about 2000 years ago. They are a study of the sensual pleasures, moral attitudes of the times and a description of the arts that one could and should pursue in one's life time to become an accomplished member of society. We in the West often study the "sexual" parts of the texts. To tell the truth, modern women would find some of the text quite patriarchal for today's standards.
The philosophy of Tantra is much older than the Kama Sutras. It was honed to its most exquisite level around 1000 years ago. To quote Nik Douglas and Penny Slinger, "Tantra is a philosophy, a science, an art and a way of life whereby sexual energy is consciously and creatively utilized." The Tantric philosophy uses sexuality as the vehicle (lessons from the Kama Sutras can be considered fine-tuning of the vehicle), but not as the destination. The destination is achieving transcendence. The ecstasy potential of the sexual experience can be used to understand the pure nature of being as part of the expanded universe. In the book Sexual Secrets, they go on to say: "Tantra is for those who wish to use the sexual bond as a means to liberation and who desire to transcend the limits of the individual self."
Therefore, we understand that the Kama Sutras are but a small, though very important, part of the Tantric philosophy. We eye-gaze not as a part of sexual enhancement but to open our soul to our beloved - that is Tantric. We learn new ways to pleasure our partners- this is the Sutras - so that we can become more capable of understanding, caring and have compassion for our partners (and, ultimately everyone) - this is Tantra.