The book is "Microeconomics" (1st edition) by Austan Goolsbee, Steve Levitt, and Chad Syverson. Please note that the book exam covers the entire book. There will be a question & answer office hour for the book exam takers in early April; the exact time and place will appear here in March.
A very good way to prepare for the book exam is to do the exercises at the end of chapters and appendices. The hardcover edition of the book includes model answers to many of the questions at the end of the book. The paperback edition is just as good for everything else. The exam may include a few questions about definitions, where you are asked to briefly explain a term from the book. Many of these would be found in the Glossary at the end of the book.
The lecture course covers also topics that are missing (or only briefly mentioned) in the book, and omits (or only briefly mentions) topics that are coverd as entire chapters in the book. The most useful additional study materials in preparation for the book exam are the end-of-chapter questions in another microeconomics textbook: Pindyck & Rubinfeld's "Microeconomics". Notice that model answers to about half of the questions can be found at the end of the book.
Calculators are allowed in the exam.
The total amount of work needed to pass or do well in the book exam is comparable with that in the lecture course (48 hours of lectures, 10 problem sets), so do not leave your preparation until the last few weeks of the semester!
The lecture course is given entirely in Finnish. If you are able to follow the course in Finnish, but are not confident in your ability to write in Finnish, then you can still attend the course. Problem sets are a mandatory part of the course - it is not possible to pass the lecture course just by taking the exams. Problem set and exam questions can be answered in English, even though the questions themselves are in Finnish. However, if you choose to use English in your answers then you must do so consistently - mixed-language answers may lead to point deductions.
Added note (due to strange requests):
The book exam grade is based solely on the points earned in the exam. There are no secret methods for earning extra credit or waivers or retakes that would be granted to students who contact the instructor directly. The course requirements are the same for all students, and they are all listed in the course web page.