Jeff Geerling has discovered in his work on the Raspberry Pi Dramble cluster that Raspbian Jessie does networking a bit differently. Whereas before (with Wheezy) it was just a case of adding some lines to /etc/network/interfaces, now you need to add some lines to /etc/dhcpcd.conf to make dhcpcd5 set the static IP address. He’s blogged about it here but just for posterity (in case his blog disappears, as others have), here are the essentials for setting a static IP for your wired connection:
So, in /etc/network/interfaces, you add:
auto lo iface lo inet loopback iface eth0 inet static address 10.0.1.60/24 netmask 255.255.255.0 gateway 10.0.1.1 dns-nameservers 126.96.36.199 188.8.131.52
And then to /etc/dhcpcd.conf you add:
interface eth0 static ip_address=10.0.1.60/24 static routers=10.0.1.1 static domain_name_servers=184.108.40.206 220.127.116.11
This should give you a static IP of 10.0.1.60.