Ingenious life and death puzzles
http://www.gobooks.info/y14.html
There are times for people of various grades completing these books at the Problem Book Grades page.
Lynx: How hard are these problems anyway?
Velobici: To answer to your question, compare the time taken per problem by Matthew MacFadyen for these books as compared to other books listed on the Problem Book Grades page.
Ingenious Life and Death Puzzles by Yang Yilun is a set of two volumes containing 200 problems, 66 elementary problems and 44 junior problems in the first volume and 46 senior problems and 44 advanced problems in the second volume. The problems appear on the even numbered pages with the answers on the flip side of the page. Answers consist of several diagrams.