Slip-stitch rib - Help?

I just purchased a new pattern book and want to make one of the sweaters. I am fairly new to knitting and have never seen this stitch combination before. The author calls it the slip-stitch rib. K1 sl 1(purlwise). How is this done? Can anyone help?

Welcome!

Just knit the first stitch, then slip the next stitch onto your right needle as if you were going to purl it, that is, right to left through the front of the loop. Don’t wrap any yarn here. Just slip, k, slip, k, slip, k. Pretty simple.

A question further just to clarify (I’ve always wondered the same thing):
If a pattern doesn’t specify whether to slip the stitch with the yarn in front or with the yarn in back, what do you do?

If it doesn’t say, I leave it where it would be for the knitted stitches in that row, back for k and front for p.

Also check out the Abbreviations Explainedpage. For the longest time I never really noticed it and had no idea there were more videos there (including ones for the slip stitches)!!