Free! Line drawing & Background mini Books

'''Free! Line drawing & Background mini Book' (Free! ミニ線画＆背景集 Free! Mini Senga & Haikei Shuu) is a series of color production books of the Free!'' anime.

Summary
There are six books in the series in total; each one having been released as a bonus alongside one of the DVD or Blu-ray volumes of the first season when bought through the KyoAni Shop. The character on the front of each book corresponds with the character/s on the cover of the respective DVD/Blu-ray it was packaged with.

As the name suggests, each book contains a mixture of line drawings of select scenes from the anime (and OVAs) as well as full color frames of key backgrounds from the series.