7 March 2022
Attached is a free, 681 page textbook: Decision Modeling. The textbook is written by David M. Tulett, Associate Professor in the Faculty of Business Administration at Memorial University in Canada.
Topics covered by the textbook include: optimization of linear, integer, and nonlinear models, as well as the use of decision trees. Both Excel Solver and LINGO are used extensively to build and solve the many example models.
According to the Introduction:
Decision Modeling involves the creation of mathematical models which represent problems faced by business management. To a lesser extent, it also involves numerically solving these models. ...
If there's a difficulty with this subject, it's probably not the mathematics. Instead, the difficulty is likely to be the building of the model which the mathematics seeks to solve. The important thing is always going from a problem description to a model for the problem.
Tulett, D. M. (2022). "Decision Modeling"
Download the full textbook as a PDF (version 3.0.4, 3 March 2022): Decision Modeling 
Updates for the textbook are available from Linney, Memorial University's Centre for Innovation in Teaching and Learning (CITL).