Ritual feats focus on the use of Rituals, an optional subsystem. These feats are not required for using rituals in the first place - instead, they make it easier to learn and use them.
Ritual Caster [Core]
Prerequisite: Casting class feature.
Benefit: You may use a ritual, even if you do not possess that ritual’s base sphere (see Rituals). If you also possess the Craft Rituals item creation feat, you still cannot research a ritual unless you meet all of its prerequisites.
Ritual Expert
You have learned much of ritual magic, and can call upon a wider variety as your needs dictate.
Prerequisites: Caster level 1.
Benefit: You may use any ritual under your magic type (arcane, divine, psychic), not only those tied to your specific tradition.
Ritual Master [Core]
Prerequisites: Casting class feature, Ritual Caster.
Benefit: You may use your MSB in place of your caster level when using rituals.
Spell Adept
Your ability to use rituals has grown to great power.
Prerequisites: Spell Dabbler, spherecaster
Benefit: When using your Spell Dabbler feat, you may increase the preparation time to 1 hour to prepare as many rituals as you desire, spending spell points for each prepared ritual. You cannot prepare more than 4 rituals of any individual level in this manner.
Spell Dabbler
You have learned to hold rituals in your memory to a minor degree.
Prerequisites: Spherecaster
Benefit: You may choose one ritual per day you may use up to the highest level you may cast. By spending 15 minutes preparing beforehand, you may cast this ritual once as a spellcaster at any point during that day. This may also be a lower-level ritual augmented by any metamagic feats you possess, so long as its effective level does not exceed that which you can cast. All drawbacks of your tradition still apply, and the spell may be augmented by any tradition boons you possess. Rather than a material cost, (unless the spell has costly material components already listed), you must spend a number of spell points at the time you prepare the ritual dependent on the level of the ritual in question: 0-2: 1 spell point, 3-5: 2 spell points, 6-8: 3 spell points, 9: 4 spell points.
Wiki Note: Many rituals have listed costs. However, these "costly" components are regular material costs if they match the price by level on the Material Cost & Casting Time table. Spell Dabbler allows you to bypass these costs. If a ritual has an expensive component that doesn't match its price by level, Spell Dabbler does not allow you to bypass it. For example, the Unseen Servant, Bound ritual has a costly component that does not match its price by level, so you cannot bypass it with Spell Dabbler.