Asa Hirvonen & Juha Kontinen 
Logic Without Borders [PDF ebook] 
Essays on Set Theory, Model Theory, Philosophical Logic and Philosophy of Mathematics

In recent years, mathematical logic has developed in many directions, the initial unity of its subject matter giving way to a myriad of seemingly unrelated areas. The articles collected here, which range from historical scholarship to recent research in geometric model theory, squarely address this development. These articles also connect to the diverse work of Väänänen, whose ecumenical approach to logic reflects the unity of the discipline.