10. Interstitial lung disease 173 David N. O’Dwyer, Bethany B. Moore and Philip L. Molyneaux 11. The lung bacterial microbiome in community-acquired and 188 nosocomial pneumonia Lieuwe D.J. Bos, Jamie Rylance and Stephen B. Gordon 12. Compromised immunity: transplantation, cancer and HIV 195 Eric Bernasconi, John-David Aubert, Angela Koutsokera, Laurent P. Nicod and Homer L. Twigg III 13. The environmental microbiota and asthma 216 Pirkka V. Kirjavainen, Heidi Hyytiäinen and Martin Täubel 14. Challenges, impact and the future 240 Michael J. Cox, Markus J. Ege and Erika von Mutius