diff --git a/free-programming-books.md b/free-programming-books.md
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--- a/free-programming-books.md
+++ b/free-programming-books.md
@@ -477,6 +477,7 @@
 * [The Art of Unix Programming](http://catb.org/esr/writings/taoup/html/) - Eric S. Raymond
 * [The Design and Implementation of the Anykernel and Rump Kernels](https://github.com/rumpkernel/book) - Antti Kantee
 * [The Little Book of Semaphores](http://greenteapress.com/semaphores/) - Allen B. Downey
+* [The little book about OS development](https://littleosbook.github.io/) - Erik Helin, Adam Renberg
 * [Think OS: A Brief Introduction to Operating Systems](http://www.greenteapress.com/thinkos/index.html) (PDF) - Allen B. Downey
 * [UNIX Application and System Programming, lecture notes](http://www.compsci.hunter.cuny.edu/~sweiss/course_materials/unix_lecture_notes.php) (PDFs) - Prof. Stewart Weiss
 * [Xv6, a simple Unix-like teaching operating system](http://pdos.csail.mit.edu/6.828/2012/xv6.html) (PDF)