(This is actually 4 reviews, I can't think of one without comparing them to the others)
(SD) Sweater Design in Plain English by Maggie Righetti
(SW) Sweater Workshop by Jackie Fee (revised edition)
(WAY) Knitting in the Old Way by Priscilla Gibson Roberts (revised edition)
(KFT) Knitting from the Top by Barbara Walker (reprinted edition)
If you're into knitting sweaters (or vests, blouses, coats, ....) these 4 are must-read's. SD especially, if you follow patterns and want to know how to adjust a pattern to fit. The other 3 pretty much assume you're not going to be following a published pattern. So does SD, but a lot of the info in there applies to adjusting a published pattern more than the other books. SD is mostly knit in pieces and sew together.
If you've never knitted a sweater and you're not sure you're ready, get SW and knit up her sampler (it's a fishy shaped piece of knitting that takes you through everything you need to know to knit almost any sweater. There's a 2nd one for color/cable work).
SW is pretty much a one-style sweater - Raglan knit bottom up. There are 1 or 2 drop shoulder sweaters, but don't depend on SW if you want to make something other than a raglan. She does have a pattern for a sewn needle case though.
WAY and KFT are definitely 'recipe style' books - how-to knit a sweater without line by line instructions. You do need your gauge and they both have chapters about the measurements you need. WAY is a bottom-up book and KFT is top-down. Most of the same styles are in both books. WAY is more percentage based than KFT. Neither one is big on customizing a fit (pretty much - knit a tube with sleeves, and wear.) If you want to customize the fit, you might need SD as well.
SD - there's a chapter on the different measurements and adjustments you can make, but then the 'how to use this info' parts are scattered in the patterns, without much cross-referencing. There's some, but still needs a little hunting imho. She has adjustments for fitting big bellies, curved shoulders, etc. The math chapter is good, but wordy enough to make a straightforward calculation go on for 3 or 4 pages. (this isn't totally a bad thing, you'll know WHY you're doing the different steps, but after you understand the why, you still need to wade through the text to do the math later)
SW - Raglans and the "why in the WORLD would you knit top-down" attitude (not a strong one, but it's there). The sampler is a great way to learn what you need to before you start a sweater - if you can do the sampler, you can do a sweater.
WAY - The basics of sweater knitting (pick up stitches, neck shaping, etc) are in one chapter then the sweater 'templates' are in another chapter so there's some back&forth if you want to go from the 'template' to details about neck shaping or whatever. There's some patterns in the back on the book, but they're not line-by-line instruction - it's more like "using template 4, make a sweater using this stitch pattern"
KFT - not much cross-referencing or indexing to find info. There's 10 or so chapters, you might be doing the sweater in chapter 6 and read "do the next steps as described in chapter 4" then when you go through chapter 4, you get "see chapter 1 for details." Definitely read this one cover to cover, at least once! OTOH, there's top-down instructions for raglan, drop-shoulder, kimono shoulder, saddle shoulder, set-in-sleeves, and square shoulders.
Depends on how involved you want to get with sweaters. If you do ok following a published pattern and get a good fit, maybe not. If you want to be able to adjust a pattern (and know why) then SD is a must. If you want to learn to design your own, SD might be enough. SW is enough if raglans work for you.
If SD is too detailed/customized for what you want, KFT or WAY is enough (which one depends on whether you want top down or bottom up). If you rather do sweaters in pieces and sew together, I think either KFT or WAY would work, but you'd have to figure out the conversion yourself. WAY gives you a little more detail about it. I prefer the style of WAY and KFT but SD does have more customizing info.
(disclaimer: This is a collaborative post between me and a blogless friend - she originally posted a similar review on a small yahoo group list a few years ago.)