Can i use weapon, expect mace fighting type weapon with spellbook? because i know most weapons is for 2-hand so it can be possible with 1-hand. And 1 another question, what specials spell scrolls have? they are more expensive and still 1 usage per spellcasting than reagents.

You can only equip a shield with a spellbook or weapon.

You do not have to have the spellbook equipped to cast spells, it just needs to be in your backpack.

A weapon that has "Spell Chanelling" on it can stay equipped while casting spells, if the weapon does not have this property it will un-equip and drop to your backpack when you cast a spell.

Spell scrolls allow you to cast the spell with a lower requirement of Magery than needed if the scroll is placed in a spellbook and cast through it.

If you use a spell scroll, you lose it, if it's placed in a spellbook, it stays in the book forever.

There is no extra benefit (as of now) to casting a spell with reagents than with not (Lower Reagent Cost).

I agree. Thanks alot for that, it helped me very much