Familiars in Steel and Glass are powerful enough to be useful. The game uses the Familiar background found at FrivYeti/Familiars.
A Library gives a character access to mystical writings, usually beyond those that he or she might own. Instead, the character has access to the writings of an organization. Your rating in Library determines both your access and the size of the library in question.
Libraries have two effects. First, every dot of Library gives you one 'specialty' die that applies to all Lore and Occult rolls made within the Library. No more than half your Library rating may give dice for a single specialty. (Examples: Fair Folk, Spirits, Demons, First Age). If you have three specialties, you may merge them into +1 die on all rolls.
Secondly, having a library gives you a chance of learning spells. Once per story, you may roll your Library rating. If your roll is successful, you may study and learn a Terrestrial Circle spell of your choice. If you have a Level 5 Library, you may roll at +1 difficulty to try and learn a Celestial Circle spell.
Due to Essence tapping, Manses are more rare in the World of Steel and Glass. A tapped Manse still produces a Hearthstone, but its Essence recovery rate is halved.
o - A Level 1 untapped Demense or tapped Manse.
oo - A Level 2 untapped Demense or tapped Manse, or a Level 1 untapped Manse.
ooo - A Level 3 untapped Demense or tapped Manse, or a Level 2 untapped Manse.
oooo - A Level 4 untapped Demense or tapped Manse, or a Level 3 untapped Manse.
ooooo - A Level 5 untapped Demense or tapped Manse, or a Level 4 untapped Manse.
Your character knows the ways of the songlines, and can tap into their knowledge. This has three uses.
First, the character may spend an hour meditating on any Wisdom-Ability issue for every die she wants to add, and then add up to her Songlines to the roll as she consults its wisdom. A total number of dice equal to the character's Songlines rating can be used in this way per story.
Secondly, the character is considered to have a tutor in all Wisdom Abilities as long as she is raising her Ability to a point equal to or lower than her Songlines score.
Finally, the character may sometimes learn spells from the songline. Once per month, the character may attempt to learn a spell; roll their Songlines, with a difficulty of 1 for Terrestrial spells and 3 for Celestial spells. If successful, the character may learn the spell normally.