Mary Thomas in her Knitting Book says the earliest knitting needles had hooks on one end and came in sets of four or five while knitting pins were in pairs; in general needles were used for round knitting, pins for flat.
The Bantam Step-by-Step Book of Needlecraft, in the section on Afghan crochet, which is worked on a single needle that looks like a knitting needle with a hook, says this might be the link between knitting and crochet and possibly the forerunner of both. It is also said to be called Tunisian or tricot stitch.
Mary Thomas in her book of Knitting Patterns has Tunisian Knitting but to my understanding this is a knitting stitch worked on two
I find working on one needle with a hook a cross between knitting and crochet. I like it a great deal!
Pictured is a scarf in progress where I am combining the Afghan stitch with wrapped and dropped knitted stitches. Shown are all the stitches on the hooked needle.
Here the stitches are half worked across in the left to right row in the crochet fashion with yarn through one loop on first stitch and then yarn through two loops for the rest of the way across the row.
Going from right to left the hook picks up the stitch from the stitch in front; this gives a woven look on the front side, a dense knit stitch on the back.
It is actually quite simple to knit with hooked needles; the hooks do not get in the way as one might think.
The Afghan stitch reminds me of weaving - so a third fibre art joins the knit and crochet!