This pdf is 89 pages long, 1 page front cover, 1 page editorial, 1 page ToC, 1 page SRD, leaving 85 pages of content, so what exactly is this spell weaving?
Spell weaving essentially is a skill-and point-based alternative to the standard vancian casting-system for arcane magic. By manipulating the strands of reality itself, hidden from the eyes of regular folks, Spellweavers can duplicate effects of regular spells. They do so via new int-based class-skill called spellweaving. In order to counteract the difficulties associated with skills being usable as often as one would like, the base-class Spellweaver also features a number of weaves per day. This means that every spell costs only one weave-attempt, but the DCs naturally vary. The base-class of the Spellweaver is what you'd expect of a primary caster: d6, 1/2 BAB, good will save, 2+Int skills per level. Spellweavers start with 4 weaves per day and can reach up to 40 at 20th level, suffer from arcane failure chance and similar traditional penalties just as much as their regular counterparts, but in order to counteract their supreme flexibility, their way of spell-casting naturally comes with a sort of penalty: If they botch their weaving attempts, the results can be dire indeed and result, when greatly overstepping one's boundaries in casting the equivalent of high-level spells too soon, in even death. No one is keeping the weaver from trying, though - potentially, this can lead to rather exiting situations at the table.
Note that not every botched attempt has to have severe repercussions and a rather complex table is provided. It should be noted that topics like collective weaving, weave-traps etc. are covered as well, making the spell-weaver feel distinct beyond his access to a wide array of known magical forces.
To make matters more exiting, the concept of weave-saturated areas (i.e. places of power) is introduced as well, making for a neat take on the trope of ley-lines and similar places of power( or dead magic). The interaction of spell-weaving and regular casting is given quite a detailed depiction and spellcraft, dispelling and spellweaving the divine is covered as well - depending on the DM's world, the gods may frown upon those who seek to usurp the powers they grant their faithful, potentially necessitating +3d4 DC to weaving divine spells. For those wanting to completely exchange the vancian casting system advice is provided as well as advice on how to handle PrCs not originally designed for the Spellweaver and how to handle tweaking them.
No PFRPG class would be complete without the customization options provided by archetypes and thus the Spellweaver also provides some: The primal weaver weaves rather intuitively (thus more unstable) and can fall into weave-powered rages. The Puppet Master is essentially the enchantment/manipulation specialist, the Reader uses his ability to perceive the weave to better avoid damage and learns to extend his/her senses and the Weaver Shaman follows a shamanistic understanding of the weave as a kind of anima universalis.
Prestige Classes specifically designed for the spellweaver are included in the package:
-The Battle Weaver (d8, 2+Int skills, full BAB, medium fort, 7 level casting progression) is a kind of barbarian/spell weaver gish that can imbue his weapon and armor with the power of the weave.
-The Cartomancer (d4, 4+Int skills, 1/2 BAB, medium will-save, full spell-progression) is an intriguing concept: By expanding senses over the weave, these fellows can create maps of surrounding areas, but without giving all the details like furniture and inhabitants away. At higher levels, their clairsentient powers improve and become more precise. I'm not sold on the d4 HD, though - according to PFRPG-design standards, that should be a d6, especially due to this PrC being anything but too strong.
-The Fated (d6, 4+Int skills per level, 1/2 BAB, medium will-save, full spell-progression) are another matter entirely - they can, via the weave, manipulate destiny itself and borrow skills and feats and even bar their foes from using them via their mystic connection to the weave. An interesting class, for sure, but one that necessitates careful watching.
-The Weave Dancer (d6, 4+Int skills, 1/2 BAB, medium fort- and ref-saves, 1/2 spell progression) is the monk/spellweaver multiclass and feels a bit odd - The table provides a better flurry of blows atk-bonus progression than a regular BAB-progression: at 10th level, it presumes +5 BAB for regular attacks and +9/+9/+4/+4/-1 for flurry of blows, which points towards a rather grievous formatting glitch here.
Next up is a new race, the Ardekh - spiderlike humanoids that worship the weave and would make for disturbing characters: They get their full age, height & weight tables, +2 Dex and Int, -2 Cha, Darkvision 60 ft., Weave Sight as a bonus feat, +2 natural armor, all-around vision (immunity to flanking when not flat-footed), +2 to Spellweaving, a climb-speed of 20ft. (and +8 to climb checks) and reduced penalties for fighting with multiple weapons. In case you didn't notice by that array of powers, a "challenge-rating adjustment" of +2 is presumed till level 6, then +1, hitting one of my absolute pet-peeves: I always hated the ECL-system of 3.5 and the balance-problems it brought and this essentially is a ECL+2-race that does not conform with PFRPG-design standards, essentially rendering the race's appeal as a player-race null and void. We also get 7 new traits, 2 of which are for the new race.
Chapter 3 deals with feats and kicks off with a vast list of feats and how they interact with spell-weaving - the level of support provided is awesome and something that sets the pdf apart - it takes the APG, Ultimate Magic and Ultimate Combat into account and lists them over several pages before introducing us to 55 new feats. These new feats are rather interesting, as they deal not only with weave-interaction, but also with adding metamagic effects to weaves( thus increasing the DC). More interesting are the elemental or specialization-style feats that increase the DC for e.g. spells with the [fire] or [acid]-descriptor, but add a burning effect, temporarily deafen foes etc. While limited in appliance, these feats do allow a customization that is nice to see. Not all of them are what I'd consider well-balanced, though: Thanatopic Spellweave for example, makes it possible to use death and negative energy effects against undead or beings sheltered by a death ward. The explanation is that the animating force is turned against them, but the repercussions of this feat are rather wide and any ability that ignores any protection from it, especially when it's such a feat, is wide open to abuse. Plus: Undead can already be hurt via positive energy. Adding negative energy to the mix just feels wrong to me. Spell Eater is another feat I consider BROKEN: If you add +5 to the DC of a save you have to make and succeed at it, you regain 1/2 the attacking spell's level, minimum 1 weaves. Can you see what this feat will make the players do? Can you see the wizards casting touch of fatigue unlimited times on their ally, the spellweaver regaining 1 weave per save? I can, and I don't like it. While most of the feats are well-designed, exceptions like these, practically screaming "Abuse me" somewhat cast a tarnish on an otherwise excellent chapter.
Chapter 4 then delivers the true meat f the book - tables upon tables that e.g. contain the modifications to the DC for regular respective levels of the spellweaver to cast (adding e.g. +27 for 9th level spells at 1st character level, ensuring that no level 1 spellweaver will meteor swarm foes to oblivion) and providing all the tools to convert e.g. 3pp-spells to the spell-weaving system: Range, school (and sub-school), area of effect, saving throw, duration, casting time etc. - everything influences the final DC of the weave and the final chapter provides the basic DCs (still to be modified by the weaver's relative level to the spell) of the spells from the Core-book, the APG, UM and UC - an awesome convenience that takes a LOT of work off your hands. Even better, an excel- calculator is included in the deal.
Finally, we get new weave-themed beasts: Apart from the Ardekhs, we get the new Loomer-race (Cr 1/2 - evil djinn-influenced creatures), varying weave-elementals, the weave-embraced template (CR +1), the undead Weave Haunt (CR 4) and the spider-like weavelings (CR 3) as well as a variant of the rotgrub hazard tat inhabits the weave. The pdf concludes with 4 pages of an extremely useful quick reference appendix. A write-up of a weave-centric goddess is also included in the deal, btw.
Editing and formatting were good, though not perfect: Some lines that should have been bold weren't etc. More important, there are some design-remnants of 3.5 unfortunately interspersed in an otherwise excellent conversion, like e.g. the aforementioned d4. The flurry of blows table of the weave dancer needs a revision. Layout adheres to a clear and easy-to-read 2-column standard and comes with beautiful full-color artworks. The pdf is fully bookmarked, comes with an artless, printer-friendly b/w-version and the aforementioned calculator, which is nice (though the calculator doesn't work with my version of excel - something you should be aware of). Oh boy. This one is oh so hard to rate. On the one hand, we get a neat, interesting alternate system of spellcasting that feels well-balanced and not half as prone to breaking as I had expected, a vast amount of support and stellar feats. On the other hand, we get a race with an ECL (that should be either just an NPC-race or needs a revision), a d4 HD in a PrC, a faulty table with another PrC and one little fact: As much as I liked the base-class, none of the PrCs or archetypes for that matter felt truly compelling. The cartomancer is a great idea, but feels a bit weak and like an excuse to give player hand-out maps, something that could also be done via other investigative means - this PrC actually needs MORE power. If you're looking for a skill-based magic-system, the spell-weaver will cater to your needs and provide a cool, flexible alternative to regular casters that could enrich e.g. a non-orthodox magic tradition in your campaign.
Were I to rate the base-class and the basic system/support provided alone, this would be 5 stars. If you're in for the whole deal, you'll have to be aware of aforementioned rough-edges, though. Should the 3.5-design-remnants I found be taken care of and e.g. the Ardekh-race nerfed to the point of being usable as a player-race, I'd gladly give the whole package 4 or even 4.5 stars. As written, though, some rough-edges of a first foray into PFRPG-rules are still evident and diminish the overall appeal of the book. Thus, for now, my final verdict will be 3.5 stars, rounded down to 3.