Multiclassing Casters?

[Alistaroc]

So if I take, say, Wizard 1/Beguiler 3, how does my spellcasting work? Do I have two separate lists? Do I get to cast as Wizard 4? Beguiler 4? What happens????

[Belzyk]

Fairly certain you get 2 different caster lists.

Youd have a wizard 1 list and beguiler 3 list

[BowStreetRunner]

The casting progression of each is separate and distinct. You are both a first level wizard and a third level beguiler.

[Togo]

The spell list, caster level, spell slots, etc. are independent of each other.

If you take a prestige class that advances spell casting, it works on only one of your spellcasting classes. (you choose each level)

[Rubik]

The spell list, caster level, spell slots, etc. are independent of each other.

If you take a prestige class that advances spell casting, it works on only one of your spellcasting classes. (you choose each level)There are, however, PrCs that advance multiple classes simultaneously, but they explicitly state that fact.

[Fouredged Sword]

If you want to play a character who casts both as a beguiler and a wizard, your best bet is ultimate magus. Note, you will lose the class feature and skill progression of the beguiler, so your mileage may vary. It is generally best to not attempt to work out two casting classes at once. There are exceptions such as a divine / arcane caster using Ur-priest or a divine / arcane caster using the duel focus of chameleon.

[Grod_The_Giant]

The casting progression of each is separate and distinct. You are both a first level wizard and a third level beguiler.
This is competently true for "normal" casters, but not 100% for most of the subsystems. Psionic and Incarnum characters share a single pool of power/essentia points, if not "caster" level or powers known. Tome of Battle classes have entirely separate maneuver pools, but stack for "caster" level.

[Fouredged Sword]

This is competently true for "normal" casters, but not 100% for most of the subsystems. Psionic and Incarnum characters share a single pool of power/essentia points, if not "caster" level or powers known. Tome of Battle classes have entirely separate maneuver pools, but stack for "caster" level.

That is to say you can cast any psionic power you know using any power point you have accumulated. You calculate your total power points by summing all the totals shown for your specific class level in each class that grants power points. A psion 10 / psiwar 3 has fewer power points than a psion 13.