It is a technique for constructing fabric that predates knitting. Instead of knitting needles, nålbinding is performed with a single sewing needle. The structure of the fabric looks very much like knitting. See the link below for more information
No one knows. The earliest form of knitted fabric that has survived to present day dates to the 3rd century C.E. It's a fragment of a sock done in the nalbinding technique rather than true knitting. The earliest true knitted fabric has been dated to around 1000 C.E. and was discovered in Egypt.
Though it is unsure where exactly knitting originated, it is probable that it began in the Middle East, the result of shepherds who invented it as a good way to use the wool from their sheep to produce clothes, since it could be done anywhere, without a big awkward loom like weaving. It is likely that knitting began as the job of men, while women spun the wool. It would then have spread to Europe through trading routes, and from there to the rest of the world eventually. The oldest known samples of knitting were found in Egypt, however, dating between the 11th and 14th centuries. In Europe, it became the art of women, and was soon a well-developed skill that was taught to most ladies. Knitting moved to America with the European colonies.