Assessment is increasingly integral to building, managing, and justifying library collections. Unfortunately, assessment can also be a daunting undertaking. And though every institution is unique, as this manual demonstrates, there's no need to reinvent the wheel. Spanning both concept and practice, Kelly offers a holistic assessment framework suitable to a variety of collections and contexts. With a structure that makes it applicable as both a training tool for practicing librarians and a useful course text for library students, this manual - introduces foundational assessment methodologies then provides concrete guidance on how to contextualize those methodologies within a holistic collections assessment program; - covers topics such as assessment goals, assessment stakeholders, selecting data and methodologies, working through project constraints, and project planning; - includes sample assessment program structures and other useful templates; - provides step-by-step instructions for more than a dozen specific methodologies, describing which aspect of the collection is being measured, what goals the methodology can address, technological requirements, recommended visualizations, and other helpful pointers; and - shares best practices for communicating effectively with internal and external stakeholders about assessment projects, with sample communication plans that can be easily adapted. Bridging the divide between the big picture and the nitty gritty, this manual guides the reader through the development and implementation of a collections assessment program tailored to local needs and resources.