Open fires are one of oldest ways of heating a home. There's something very primal and instinctive about an open fire. The gentle sound of the flames lapping and the flickering of the flames are very soothing. Log fires are pretty good for the environment, too, as using wood as a fuel encourages people to plant more trees. And not all the carbon in wood is released back to the atmosphere when a log is burned (what do you think the ash and charcoal left behind is made of?), so it's probably a carbon-neutral heating source, even if the smoke isn't all that pleasant in large quantities, although small amounts of wood smoke smells quite pleasant, especially from pine or apple logs. Wood ash is good for the soil, and is perfect for reducing acidity in soils - I've even seen a potato growing in nothing but wood ash. Coal, however, is another story. This is a fossil fuel, so burning it adds to carbon emissions, and the ash is pretty toxic, too, and the smoke is never pleasant.
However, fire is one of those primitive things that is very pleasant and relaxing in the right place and in the right amount, but is devastating if it gets out of control. You only have to read the news bulletins about bushfires in California or Australia to see what the effects of out-of-control fires are. Britain isn't immune from fires, either - just ask the local fire brigade. Enjoy your open log fire, by all means, but remember to keep things safe.
First of all, make sure that your chimney is sound and that it is swept regularly. Soot building up in chimneys is a common trigger for fires, as soot is pure carbon, which is flammable. Do not try to clean a chimney yourself - get a professional chimney sweep in (and no, they won't wear a tall hat and you can't kiss them for good luck).
After chimney fires, sparks are the next most common cause of house fires that are started from the fireplace. All fires snap and spit a bit, although some types of wood are worse than others. Pine logs seem to be the worst offenders here, but you can use these in an open fire if you take basic precautions. First of all, never leave a fire unattended. Overnight and when leaving the room, put a spark guard in front of the fire. This will stop sparks flying out into the room. Remove it when you come back in, as it does stop the heat getting out into the room, too.
The sparks will still fly out. This is why most open fires are constructed with a hearth made of stone, brick or concrete in front of it. This is where most hot embers and sparks will fall, so remember to keep this area clean and clear from pine needles, leaves, ends of matches and the like. Most embers will go out pretty quickly if they fall on an empty hearth, as they have no more fuel and they lose their heat quickly. However, some sparks and embers can go beyond the hearth area. Always have a metal shovel nearby and use this to pick up the fallen ember. Sparks can merely be thumped out with the bottom of the shovel.
To prevent your carpet or other flooring being damaged by flying sparks and embers, use a hearthrug. This will get pretty singed by flying sparks, and that's the point. It's small and replaceable.
To prevent things (including people) falling into the open fire and getting burnt, use a fireguard. This is larger than a fireguard and won't stop sparks. In fact, a fireguard should be used around any radiant heating appliance. One bonus is that you can dry laundry on a fireguard, as long as you don't let things get too hot - keep an eye on them!
Use your smoke alarms, but be aware that if the fire smokes a bit, as often happens when you're trying to "draw" it and this will set the alarm off. Annoying, but necessary.