Although SQL is widely used by data practitioners for analytics, it may not be well suited for applications that require developers to concisely express recursive queries (e.g. machine learning, graph analytics, knowledge management). In contrast, Datalog is a logic programming language that more elegantly supports recursion as well as aggregation in recursion. BigDatalog (a parallel, distributed Datalog engine) was developed in 2016 to execute Datalog queries over large datasets. In this demonstration paper, Li et al. present Logic Library (LLib), a library of recursive algorithms written in Datalog (e.g. for graph search, machine learning, data mining) to run on BigDatalog. LLib, which provides a unified interface similar to Spark MLib, is fully compatible with DataFrame APIs so that it can be used with existing Spark functions.