Before chasing a Spellbook, identify its source: skill tree, attribute-gated shop purchase or boss-unlocked craft.
Race and Class spells come from the skill tree
The developer describes Race + Class spells as the class-specific layer gained through the skill tree. Modifiers can customize the result, so the base spell name is only part of the build decision.
Universal Attribute Spells come from shops
Universal Attribute Spells are obtained by purchasing Spellbooks from shops. They require specific attribute thresholds, but the resulting spells can be used by any Race and Class.
Boss Spells come from crafted Spellbooks
Boss Spellbooks are crafted after defeating the relevant boss and unlocking the ability to craft them. Some may also require attribute thresholds, and the spells are described as usable by any Race and Class.
Build around the three sources together
The developer's framework combines Race/Class spells, universal attribute spells, Boss Spells, equipment sets and passives. A build page should therefore show acquisition source and requirement next to each spell, not only list damage or element.
Ruined Spellbook is an intermediate state
A current Wildwood report says a ruined spellbook first unlocks a restore recipe rather than teaching a spell immediately. Keep the ruined item, then use the relevant Guild Hall book-processing NPC to make the restored, usable Spellbook. The NPC, materials and cost still need client capture, and Light Reading only confirms that the ruined book was found.
Current verification boundary
The source confirms the acquisition model, not the complete EA shop inventory, threshold values, recipe costs or final skill-tree placement. Those fields remain pending current-client capture.