The best all-around introductory book on mathematical modeling is How to Model It: Problem Solving for the Computer Age by Starfield, Smith, and Bleloch.
The book dates back to 1994, but is just as relevant today.
When most direct marketing people talk about "modeling", they either mean predictive response models, or they mean financial spreadsheet P&L models.
This book goes far beyond these applications, and teaches the skill of crafting novel models to help provide insight into a wide range of problems. It teaches the reader how to think about a problem, craft a mathematical representation, then use that representation
Topics include model scope, heuristics, spreadsheets, risk, stochastic modeling, rudimentary optimization, dynamics, trade-offs, and expert systems.
The book isn't a dry academic text book. Rather, it is a series of exercises and questions that teach modeling concepts in a hands-on manner.
Highly recommended for analysts in any field.